It looks like the commit needed to fix this is f3aefb6a7066e24bfea7fcf1b07907576de69d63, which is in the bionic's linux kernel 4.15.0-20.21 (as commit 17dd0448ee23bbd898c2a9463eb0d0890b29ca02). The corresponding linux-hwe and linux-hwe-edge kernels are in xenial-proposed, going through the kernel Stable Release Updates process. Confirming that the kernel in proposed indeed fixes the issue would be appreciated. Thanks!
It looks like the commit needed to fix this is f3aefb6a7066e24 bfea7fcf1b07907 576de69d63, which is in the bionic's linux kernel 4.15.0-20.21 (as commit 17dd0448ee23bbd 898c2a9463eb0d0 890b29ca02) . The corresponding linux-hwe and linux-hwe-edge kernels are in xenial-proposed, going through the kernel Stable Release Updates process. Confirming that the kernel in proposed indeed fixes the issue would be appreciated. Thanks!