Rye flour paste cracking open at one joint

[00Buck]

Hey yall. Had a little issue my last run and wanted some input if anybody would give me some. Ive done many many runs but this was my first time dealing with this.

I use a rye flour paste. Its always worked flawlessly. But this morning at the 90 going down to my worm the seal just kept breaking open. I had paste at 6 other connections (I run a thumper) and they all did fine. When Id patch a leak the other side of the elbow would crack almost immediately. Does anybody know what would cause that? I wound up wetting a cut up bandana and wrapping it around the paste and joint just to finish my run out.