I can confirm that:
1) rolling back to the latest mainstream kernel for 18.04 is broken (4.15.0-22-generic)
2) Installing the updated kernel from bionic-proposed does fix the problem (4.15.0-23-generic)
I can confirm that:
1) rolling back to the latest mainstream kernel for 18.04 is broken (4.15.0-22-generic)
2) Installing the updated kernel from bionic-proposed does fix the problem (4.15.0-23-generic)