Hi,
It did sound familiar which is why I asked.
The reason for this problem then is indeed because of the use of Tuxera and having the external disk formatted as NTFS.
While changing the partition to a native macOS file system should address it, have a look at this thread:
Fusion 11 Trial on Mojave and VM on external SSD
There it is claimed that Tuxera have patched their drivers to fix this particular issue.
Personally I would prefer to keep my VMs on a native file system, but if using NTFS works better for you, then use what works better.
Be careful though with host macOS updates and test the tuxera drivers after an update first with a slightly less important VM.
Another thing to note about running VMs from an external disk is that you should keep good backups (Not Time Machine! ) of your VMs as an accidental disconnect between host and external disk might corrupt the VM. FWIW, I also ran VMs from an external SSD for years without any corruption problems, but it is good to be aware of any potential pitfalls.
Hope this helps,
--
Wil