As per title
Reproduction Steps:
  1. Enable Logging for U#
  2. Attempt to log anything from Vrchat using the Debug.Log function in a world
  3. While the log entry will exist in logs, no log will be detected by U# as the format for the logs is not what was anticipated when u# was built.
I recommend upgrading U# to the latest available version as it is significant out of date https://github.com/MerlinVR/UdonSharp/releases, but if not, maintaining the tool so it can properly catch logging would be useful for all world developers.
I agree with VRC that reverting the logging back to double spaced is not ideal, so I recommend fixing the tool