Modifying files with one replica gives read-only file system

Dear fellows,

We have this situation on some files that return the error read-only file system when the users try to modify them.

We noticed that all these files miss a replica. The strange thing is that for many of these files, the unique replica is in fact valid, and matches the metadata in the MGM.

Indeed doing such a procedure on such a file gives the following:

$ echo test | tee file.txt
test
tee: file.txt: Read-only file system
# eos file adjustreplica test.txt
success: scheduled replication from source fs=3163 => target fs=3103
$ echo test | tee file.txt
test
$ #OK

We were wondering if such files that just misses one replica isn’t supposed to be repaired by the fsck repair thread (which is now enabled on our instance) ? The files that are concerned are not newly created files, and indeed one of them was blocking a process for several days because it would always block on that file, this is how we noticed this issue.
And in addition, since the file is perfectly readable because the replica is healthy, we were thinking that modifying the file could well update just the existing replica and go on.

This doesn’t concern many files (only 16 different ones since the beggining of the year, with a total of 79 operations according to the logs) but is blocking for people using one file. But we potentially have other files with one replcia that would fail being modified if we would try to do that.

Did someone had also such a case in his instance ?