After discussed today 2 possible root cause:
1- insulation crimping not appropriate, the shape push out insulation during crimping and it is easier for insulation to slide out. 2 dies were approved one is not appropriate and will be removed from specification. Pending pieces returned or more piectures to confirm this root cause.
2- manual positionning not appropriate (could be the case even if cusotmer comment is only about stripping length). Temrinal positionning can be automated and positionning in terminal can be improved by investment: vbrating bowl or insulated terminals in tape or trminal covered by sleeve.