Removing an Item Frame triggers both frequency 11 and 15

Normally, frequency 11 only detects block changes, and frequency 15 signals death of non-living entities. So why is frequency 11 triggered and at the same time?

Steps to reproduce:

1. Place two calibrated sculk sensors

2. Point a comparator into both and provide them with a signal strength of 11 (this is most easily achieved with a lectern and a fifteen page book on page 11) for block changes and the other with 15 for dying entities

3. Place an item frame

4. Break the item frame

Observed behavior:
Upon removing the item frame, both frequencies 11 and 15 are triggered

Expected behavior:
For any given action, only one sculk sensor signal should trigger. The item frame triggering two is inconsistent with all the other behaviors (except MC-271242), but more importantly, frequency 11 doesn't quite make sense with the other things that are grouped in with ("Block changes state (chiseled bookshelf, lectern, composter, decorated pot, bell ringing, item frame, etc.)" - https://minecraft.wiki/w/Sculk_Sensor). It would make more sense to only trigger 15, like other non-living entities, for example, armor stands do.