Don't know where to really report the bug/error so here we are.

character.ITEM_CREATE

{"item":{"metaItems":[],"customData":{},"spells":[],"limitedUse":null,"definition":{"grantedModifiers":[{"id":"armor_23257_22934","entityId":null,"entityTypeId":null,"type":"bonus","subType":"armor-class","dice":null,"restriction":"","statId":null,"requiresAttunement":false,"duration":null,"friendlyTypeName":"Bonus","friendlySubtypeName":"Armor Class","isGranted":true,"bonusTypes":[],"value":2,"componentId":23257,"componentTypeId":112130694},{"id":"armor_23257_22941","entityId":null,"entityTypeId":null,"type":"bonus","subType":"magic","dice":null,"restriction":"","statId":null,"requiresAttunement":false,"duration":null,"friendlyTypeName":"Bonus","friendlySubtypeName":"Magic","isGranted":true,"bonusTypes":[],"value":2,"componentId":23257,"componentTypeId":112130694}],"baseItemId":8,"baseArmorName":"Shield","strengthRequirement":null,"armorClass":2,"stealthCheck":1,"id":23257,"baseTypeId":701257905,"entityTypeId":112130694,"canEquip":true,"magic":true,"name":"Lion Shield","snippet":null,"weight":6,"type":"Shield","description":"<p><em>This enchanted golden shield is fashioned to appear to be a roaring lion&rsquo;s head. Occasionally the lion lets out a long yawn or a quick sneeze, then returns to its resting position.</em></p>\r\n<p>While holding this shield, you have a +2 bonus to AC. This bonus is in addition to the shield's normal bonus to AC. You also have a +2 bonus to attack and damage rolls made with the shields <strong>bite</strong>&nbsp;ability.</p>\r\n<p><strong>Bite.</strong> Three times per day as either a bonus action or reaction,&nbsp;you can command the Lion Shield to animate and attack (bite) one creature of your choice within 5 feet of it. The shield uses your attack roll and ability score modifier to damage rolls, dealing1d8 piercing damage on a hit.&nbsp;</p>","canAttune":false,"attunementDescription":"","rarity":"Rare","isHomebrew":true,"version":"1","sourceId":null,"sourcePageNumber":null,"stackable":false,"bundleSize":1,"avatarUrl":null,"largeAvatarUrl":null,"filterType":"Armor","cost":null,"isPack":false,"tags":["Combat","Warding"],"additionalDamages":[],"reach":null},"proficiency":true,"quantity":1,"searchTags":[],"entity":{"baseItemId":8,"baseArmorName":"Shield","strengthRequirement":null,"armorClass":2,"stealthCheck":1,"id":23257,"baseTypeId":701257905,"entityTypeId":112130694,"canEquip":true,"magic":true,"name":"Lion Shield","snippet":null,"weight":6,"type":"Shield","description":"<p><em>This enchanted golden shield is fashioned to appear to be a roaring lion&rsquo;s head. Occasionally the lion lets out a long yawn or a quick sneeze, then returns to its resting position.</em></p>\r\n<p>While holding this shield, you have a +2 bonus to AC. This bonus is in addition to the shield's normal bonus to AC. You also have a +2 bonus to attack and damage rolls made with the shields <strong>bite</strong>&nbsp;ability.</p>\r\n<p><strong>Bite.</strong> Three times per day as either a bonus action or reaction,&nbsp;you can command the Lion Shield to animate and attack (bite) one creature of your choice within 5 feet of it. The shield uses your attack roll and ability score modifier to damage rolls, dealing1d8 piercing damage on a hit.&nbsp;</p>","canAttune":false,"attunementDescription":"","rarity":"Rare","isHomebrew":true,"version":"1","sourceId":null,"sourcePageNumber":null,"stackable":false,"bundleSize":1,"avatarUrl":null,"largeAvatarUrl":null,"filterType":"Armor","cost":null,"isPack":false,"tags":["Combat","Warding"],"grantedModifiers":[{"id":"armor_23257_22934","entityId":null,"entityTypeId":null,"type":"bonus","subType":"armor-class","dice":null,"restriction":"","statId":null,"requiresAttunement":false,"duration":null,"friendlyTypeName":"Bonus","friendlySubtypeName":"Armor Class","isGranted":true,"bonusTypes":[],"value":2,"componentId":23257,"componentTypeId":112130694},{"id":"armor_23257_22941","entityId":null,"entityTypeId":null,"type":"bonus","subType":"magic","dice":null,"restriction":"","statId":null,"requiresAttunement":false,"duration":null,"friendlyTypeName":"Bonus","friendlySubtypeName":"Magic","isGranted":true,"bonusTypes":[],"value":2,"componentId":23257,"componentTypeId":112130694}]}},"quantity":1}

There was a problem accessing that item.

ActionApiError: Bad Request
at new t (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:49323)
at https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:50:392576
at r (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:244516)
at Generator._invoke (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:245636)
at Generator.e.(anonymous function) [as throw] (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:244695)
at h (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:120253)
at Object.n [as cont] (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:121066)
at g (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:120885)
at r (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:119264)
at Object.e.cont (https://www.dndbeyond.com/Content/1-0-134-0/React/CharacterTools/dist/characterSheet.bundle.min.js:23:119351)

This is a homebrew item. A few known possible causes are:

1. This item is public homebrew shared to you via a campaign. Currently there is a bug that causes an error when trying to use a homebrew shared this way.
2. There is a problem with the way the item's modifiers are set causing the error. If you made it, post a link to the item. If someone else made it contact them.