AxCrypt does *not* split files. There is no limit except available storage concerning file size.
AxCrypt will use a digit suffix (but not quite like you’re showing) in certain situations when there’s a file name collision but that does not seem to be the case here.
If you have a file named “MyVirtualDisk.vhdx”, and you encrypt it, you will get a file named “MyVirtualDisk-vhdx.axx”.
Are you sure you’re using AxCrypt ;-) ?