It’s hard to say. If the seal has been working well before releasing after some time in use then it seems unlikely to be specifically a chemical issue. I’m aware that potting sometimes fails due to exposure to temperature extremes, but it’s unclear how you’ve been storing and transporting your equipment so no idea if that’s likely here. It can also fail if exposed to too much pulling/stress.
It’s worth noting that difficulty in achieving consistently robust and reliable results with potting, and in predicting when a failure is likely to occur are key reasons we’ve developed and predominantly moved to using compression-based WetLink Penetrators. Where possible we’re also working to develop epoxy-less alternatives for our other products.
From a post on why the (potted) BlueESC was discontinued: