Halyard Wrap
The common cause for this is halyard wrap.
Did you install the halyard restrainer that came with the unit?
Especially when the halyards are close to the stay at the top, (Some are a lot farther away then most of the Ericsons). The halyard wraps when you are trying to roll it up. It is not unusual for this to seem to happen only on one tack.
The other issue with this is that people have sometimes managed to get their spinnaker halyard wrapped up in the top of the roller furling also.
You may need to go up top and look. Most of the issues are up there, few are on the bottom end.
Another thing to check is forestay tension..
Guy