Surface Contamination on Thermoset Plastics

I am inspecting the quality of Thermoset plastic injection moulded parts. Recently there is an issue occurring to some of the parts, which is failed bond strength. The parts assembling with this thermoset parts are glued and then went for the bond test. But unfortunately , due to some reason, this adhesive is not sticking on the surface of the Thermoset part and eventually failed the bond test. I went for edx testing on the affected part , but it could not find any anomaly on the raw material content.

What I tried as of now ;

1. Check the raw material content using the edx Method-----------------------Ok
2. Check the mould cleaning method & check the releasing agent -------------------Ok - Using IPA & Lubest (RS#6) non-silicon (from the beginning itself following the same).
3. Check the storage condition.-----------------Ok
4. Checked the handling of the finished parts--------------------Ok (Using clean gloves while handling the parts)


I need the expertise advise here. Thank you in Advance.