This appears to be bug #1781001, which was fixed in dkms 2.3-3ubuntu9.2 for bionic. Have you not upgraded to the current version of the dkms package from bionic-updates?
This appears to be bug #1781001, which was fixed in dkms 2.3-3ubuntu9.2 for bionic. Have you not upgraded to the current version of the dkms package from bionic-updates?