Head gasket woes
I was taught real early that bending steel (beam type wrench) does not go out of calibration. Steel strength just does not change. So I rarely use my click-type but have it...well...not sure why I have it!!
If I was not just a hobbyist and needed it to do faster/prod work, I'd for sure use click-type wrenches and get them calibrated often.
Glad the OP found the issue!