Bitmap font glyphs used for chest GUI background render after items in 1.21.6

My resource pack uses a custom bitmap font to render a GUI background via a Unicode glyph. The default font file is defined as follows:

{
  "file": "skyup:unicode/tlo/rankingi_prac_lowcy.png",
  "chars": ["\uE118"],
  "char": "",
  "height": 256,
  "ascent": 21,
  "type": "bitmap"
}

This worked correctly in versions 1.21.4 and 1.21.5, where the background glyph was rendered behind other GUI elements (items). However, in version 1.21.6, the rendering order seems to have changed? It looks like the bitmap glyph is now rendered on top of GUI items, effectively covering or obscuring them.

When I remove the Unicode background glyph from the screen, all GUI items render normally.

Steps to Reproduce:

1. Create a resource pack with a bitmap font using a custom glyph as background (see above).

2. Use the glyph in a ex. chest GUI name.

3. Load the pack in 1.21.5 — glyph renders behind GUI items.

4. Load the same pack in 1.21.6 — glyph renders on top of GUI items.