Hey there,
Quick update:
A fix for the neverending loading screen on PVE-C servers has been completed internally and verified, and is currently being targeted for release with Update 2.6. This fix cuts down dramatically on the system that was causing game clients to time out while attempting to join PvE-C servers. While it is difficult to confirm it will fix every single case of this issue, as there are a plenitude of circumstances that could affect this, it does seem to have a possitive impact on most configurations.
There is no ETA yet for the release of 2.6, but once it hits Testlive PC, expect it to be on consoles and PC live in 3 to 4 weeks after that.