Some modern filesystems such as CephFS have a protected folder called .snap that hence cannot be used for SNAP. I wonder if you would consider changing this in your docker images?
For example one could change ${HOME}/.snap to ${HOME}/.esa_snap. In this case the following changes are needed to the files in [snap installation dir]/etc:
In snap.properties you need to change the property snap.userdir.
For example sit it to: snap.userdir="${HOME}/.esa_snap"
Don’t forget to remove the ‘#’ at the beginning of the line.
In snap.conf you need to be change the default_userdir.
Here change the default_userdir="${HOME}/.snap/system"
to default_userdir="${HOME}/.esa_snap/system"