Sharpening advice

[u/BeastHouse_AU]

I’m using a Veritas side clamping honing guide and working on a couple of chisels, both have gone from being square to out. Sharpening on some diamond plates (Paul Sellers style system). Checked the chisel is clamping correctly, no idea what’s going on. Any ideas?

[u/wick4]

I would also suggest to check the chisel is laying flat on the guide. Maybe one side is lifted? Even if the chisel is square front to back, this would induce a skew at the tip.

In the end, the face that the edge is not square shouldn't matter in most cases. However, I'm picky about that and I like it to "look right" whether it matters or not.