Adding country TR or RO throws error

[frankofno]

When blocking the following countries:

/usr/local/bin/nft-geo-filter --table-family netdev --table-name SOMETHING --interface xxxxx --no-ipv6 --provider ipverse.net CN RU RO TR IR ID MY VN TH SG IN UA

As soon as I add RO or TR to the list, I get

ERROR - update_filter_set - Could not add the "tr" IPv4 blocks to the filter-v4 set in SPAMMERS
WARNING - restore_old_sets - No old sets detected. Setting the SPAMMERS table as dormant!
ERROR - show_subprocess_run_error - Failed to run: (1, ['/usr/sbin/nft', '-f', '/tmp/tmpegg9lql6/tmp08la9pc5'])
ERROR - show_subprocess_run_error - Command exit status: 1

ERROR - show_subprocess_run_error - Command stdout: 

ERROR - show_subprocess_run_error - Command stderr: 
/tmp/tmpegg9lql6/tmp08la9pc5:2:5-13: Error: Could not process rule: Directory not empty
set filter-v4 {
    ^^^^^^^^^

Using only RO or TR works fine.
Using CN RU TH MY SG works fine.
But not CN RU RO TR IR ID MY VN TH SG IN UA

Any hint what could be the problem?