You may have seen my other thread stating the exact same problem (I didn’t see yours before I resurrected mine otherwise I would have just posted here).
Viscous made mention about the outer diameter of my conduit, since I am using the international version (Australia) which is designed for 25mm conduit but the conduit I got was actually 25.4mm. Doesn’t sound like a lot but it means everything is a tight fit and things get bent out of shape. In addition my conduit is aluminium which is not strong enough and is soft enough for it to be bent out of shape quite easily with the forces involved.
So I am currently printing out the new corner pieces, and tomorrow will be getting 25mm OD galvanised steel conduit to replace all the aluminium rubbish.
I am pretty confident this is going to solve a lot of the issues I have been having so once I have it done I shall comment here with the results.