Tile offset/overlap?

[jbarth-ubhd]

We're using openlayers 9.0.0 and cantaloupe IIIF server (from static jpg images); if I'm zooming very deep, I'll see some misalignment/offset in the tiles:

Steps to reproduce the behavior:

1. Go to coming soon
2. Click on coming soon
3. See https://digi.ub.uni-heidelberg.de/diglitData/v/openlayers-tile-offset.png

I'll expected the area (center of the image, ligature 'ch') looking like this:
https://digi.ub.uni-heidelberg.de/diglitData/v/openlayers-tile-montage.png

produced with

wget -O k00.jpg https://digi.ub.uni-heidelberg.de/iiif/2/cpg848:004v.jpg/512,256,256,256/full/0/default.jpg
wget -O k01.jpg https://digi.ub.uni-heidelberg.de/iiif/2/cpg848:004v.jpg/768,256,256,256/full/0/default.jpg
wget -O k10.jpg https://digi.ub.uni-heidelberg.de/iiif/2/cpg848:004v.jpg/512,512,256,256/full/0/default.jpg
wget -O k11.jpg https://digi.ub.uni-heidelberg.de/iiif/2/cpg848:004v.jpg/768,512,256,256/full/0/default.jpg

montage k[01][01].jpg -geometry +0+0 out.png

[mike-000]

Are you using WebGLTile layer with IIF? If so you will see tile edge effects when overzooming which could be avoided if the tiles were treated as having a gutter, see #15577 (comment)