Unarmored Defense
Beginning at 1st level, while you are wearing no armor and not wielding a shield, your AC equals 10 + your Dexterity modifier + your Wisdom modifier.

Unarmored Movement
Your speed increases by 10 feet while you are not wearing armor or wielding a shield.

I have a Monk/Fighter character.  Fighters have Shield proficiency, but, as above, using a Shield limits Monk abilities (rightfully, so).  However, this is not what happens when on my D&D Beyond character sheet and has been like this since a 2018 forum post I found.  For example:

When I have no shield, I have 45 movement (30 + 15 unarmored movement), and AC is 16 (10 no armor + 4 DEX + 2 WIS for Unarmored Defense) and my unarmed strikes show correctly as Monk enabled (proficient with a Martial Arts die worth of damage, ie. 1d6+mod).

When I equip a shield, I, still, have the same 45 movement (30 + 15 unarmored movement), and AC is bumped to 18 (10 no armor + 4 DEX + 2 WIS unarmored defense + 2 shield).  The movement should be 30, and the AC should be 16 from a calculation (10 no armor + 4 DEX + 2 shield).  They only thing affected are the Unarmed Strikes which are, now, using RAW stats for striking (Str mod for attacking and Str mod+1 for damage) showing the system does, in fact register the shield in place and it affecting the Monk abilities.

So, the other aspects of this are incorrect.  The only time a shield should not affect Monk ability is the epic Animated Shield because it allows the shield to float with a command word freeing your hands, thus enabling the monk abilities to reactivate while still maintaining the shield bonus (for 1 minute per bonus action to activate it).  So, my question is, will this miscalculation be fixed.  The system works great and it is marketed as doing all the work for a player using trustworthy calculations, but this hurts a player.