Shelf "align_items_to_bottom" block entity field does not align items to bottom

After the change from shelf item alignment being a block state to a block entity field in snapshot 25w34a, the rendering position for shelf contents when aligned to the bottom appears to have broken, with blocks and items being unmoved, and items with special models being raised or lowered incorrectly. This is consistent in 25w35a. Items that are misaligned from some testing are shields, beds, lecterns which are raised, and heavy cores, conduits, chests, enchantment tables, fence gates, trapdoors, pressure plates, buttons, daylight sensors which are lowered but not by enough to touch the bottom. Of note is that no items ever touch the bottom of the shelf as in the previous implementation, as even blocks that are large enough when aligned to the centre are instead raised in “bottom align” mode.

Steps to reproduce: Place a shelf block, modify its data to use bottom-align mode (i.e. /data modify block 12 -59 7 align_items_to_bottom set value true)

Expected result: Contained items are rendered touching the bottom of the shelf, as in 25w33a when using the align_items_to_bottom block state, and in 25w32a by default

Actual result: Contained items are rendered in the middle of the shelf. Items that do not use regular models such as beds and heavy cores are offset from the centre in varying ways.