Same issue: https://imagenes.digitalsmartstorm.com/archivo/nullrankmath.png
Urvanov Syntax Highlighter 2.8.24 – RankMath Pro 2.15.0 with RankMath “Core” 1.0.71. PHP 7.4.
I did rollback of Urvanov and the problem continued.
I also rollbacked RankMath and I haven’t been able to solve it either.
However, deactivating Urvanov solved the problem.
OPCache purging after each action.
