I have the same problem.
I overclocked my 9700K to 5 GHz on all cores and set an AVX offset of -3. With ICUE 3.26 and 3.25 my CPU clocks to a maximum of 4.7 GHz and without ICUE to 5 GHz (for games and benchmarks).
If I change the AVX offset e.g. to -2 or -1 the CPU clocks to 4.8 or 4.9 GHz.
Maybe the software programmers should have a look at the difference between ICUE 3.25/3.26 and ICUE 3.24, because I have no problems with ICUE 3.24.
Greetings
Mainboard : Asus Maximus Hero XI Wifi