I would suggest you not only have HF, human error issues, but also a level of non-compliance.
We all make errors & (for what we believe are good reasons) we don't always comply with procedures. Whether this is situational or the norm, at some stage we 'ALL' break the rules.
It seems like your organisation operates a blame/shame culture. You need a means of sharing experience regarding error & rule breaking. If you don't operate within a fair/just culture, no useful dialogue can take place.
HFACS & the Boeing MEDA (Maintenance Error Decision Aid) are useful, tools for improvement & education. Unfortunately the most elegant of investigations are useless unless results are acted upon & all players treated even handed’ly.
If people are punished for error, no one will highlight errors, few learn from them & eventually you'll end up with a catastrophic event.
You should have a confidential reporting scheme. If you’re EASA, your maintainers should fall under the mantle of an EASA Pt 145 maintenance organisation. All 145 organisations must operate some form of error management, error reporting system. If your organisations systems are nonexistent or don't work try CHIRPS, MOR & if the engineers mandated reporting system doesn't work they can do likewise.
It a shame but a lot of organisations are still only tick in the box compliant, the regulators need to get tough.