Comment 3 for bug 1852611

The extra } is a consequence of multiple things, like no good recover found, or invalid linux entry data. I guess your bug should rather be a duplicate of bug #1848856.

In any case, both of them are fixed in this ppa (https://launchpad.net/~ubuntu-desktop/+archive/ubuntu/zsys) before we release an SRU for eoan. Do you mind giving it a try and report it fixes your issues?
Thanks!