I have two separate projects within an Adobe Production
In Project A I have a multicam clip, and the footage inside the multicam clip is offline
I paste the multicam clip onto a sequence in Project B - the footage remains offline
I reattach proxies to the footage in Project A, making the footage in the multicam online when I load it into the source monitor
Back in Project B, the footage within the multicam remains offline in my sequence.
Even when I match frame on the multicam clip in the sequence to load it in my source monitor, it still appears offline. Even if I duplicate the original multicam clip in Project A and paste this duplicate onto a sequence in Project B, it still appears offline.
My workaround has been to duplicate the source clips in Project A, add those to a new multicam, and use that new multicam in Project B.
It feels like the issue is that Project B is somehow "remembering" that those clips are offline, so when they are used in ProjectB they appear offline regardless of their true status.
On a side note, Adobe in all its consistency also works the other way:
I have a multicam clip in Project A, and the footage within the multicam is online
I add the multicam clip to a sequence in Project B, everything is still online
I offline the footage within Project A. When I open the multicam clip in Project A in my source monitor, everything is offline
In Project B, the multicam footage remains online, and can playback even though it's not linked to anything at its source