CP spending bug

[Lychwood]

I had hoped this was the same bug causing the CP spending problem with spells, but it has persisted after the patch so here's a writeup:

This is happening on CharID 8623.

Whenever I go to spend CP on a tier 3 skill, I get this error message:

I haven't done any buybacks since the last tier 3 skill I bought, so I don't know what changed to cause this. The numbers work out, too. I've spent:
90 T1 CP
160 T2 CP
So I should have spent exactly the 250 needed.

[nopedope]

u only spend 70 in tier 1. thrown weapons - 10 cp, advance thrown - 20 cp.

[Nayru]

the likely snek is correct, you're 20 cp off

[Lychwood]

the bug was my brain all along!

no patch can fix