Trouble with rndc sync / re-writing zone files after nsupdate

[t11s]

Thanks for the great work on this docker! I am able to perform nsupdates to zone files, which lead to writing out journal (.jnl) files, however if I issue "rndc sync" to try to write out the updated zone file, it doesn't get written out and I get this:

28-Aug-2020 17:41:26.828 received control channel command 'sync'
28-Aug-2020 17:41:26.829 file.c:393: unexpected error:
28-Aug-2020 17:41:26.829 unable to convert errno to isc_result: 16: Device or resource busy
28-Aug-2020 17:41:26.829 dumping master file: rename: db.workshop.nmos.tv: unexpected error

It does look like it writes out a temp file with the updates with a filename like tmp-utRxaCMV4D.

Any help on a suggested config to be able to write out updated zone files would be great, thanks!

[resyst-it]

Can you explain me your setup please ?
Maybe a lib is missing from the Alpine image.