I am having the same issue. I'm using a custom scroll with charges to track spell points that are supposed to reset on a long rest but they don't reset. I also have tried making the scroll require attunement out of curiosity and it seems like it is not registering as an attuneable item either.
Scrolls are generally a 1 time use item which is probably why you cant set it as an attunement item. Try changing the item type to Wonderous Item and just have the description state that it is a scroll.
As of this post it seems this has not yet been addressed.
For anyone interested, I have found a fairly reasonable work around. I created a custom feat to go along with my item, which allows you to add "limited uses" under the Actions section. The item description says something along the lines of "While wielding this weapon you gain the benefits of the <Custom Feat> feat" and I let the player who has the item add the custom feat (at the bottom of Features and Traits).
Adding an action with limited uses works with the designated rest type and resets like everything else!
I totally agree that this needs to be fixed. Is there a button to add to the "long rest" option that says (new dawn?) or something like that. Or just add a separate new dawn option. It seems to me that a long rest would only happen once per day anyway, but that depends on how each campaign works I guess.
This problem if it was fixed it is back, if it hasn't been fixed its still an issue. I created an item that would allow the player to cast a spell once per short rest, yet when we click take short rest it does not reset the charge on the item. I tried switching it to long rest to see if it would work there and still nothing. I also switched the item from non-attunement to attunement to see if that was the problem and it still wouldn't work.
Really? Because when adding charges to a homebrew item, the form asks for:
Has Charges (checkbox)
Number of Charges (value input)
Charge Reset Condition (dropdown)
If I select "Long Rest" for the Charge Reset Condition, these charges should be reset when clicking "Long Rest" on the character sheet. This is not an ambiguous reset method. It is clearly defined when the item was created.
EDIT: Also, this is exactly how actions with limited uses behave when added to a Feat, which is what I was forced to use as a workaround. The behavior is already programmed into the system, it just needs to be applied to items as well as feat actions.