You could try the patch (i.e. use the -current version). While wiz still seems to experience problems, I cannot reproduce them anymore with the fix.
I tried with the patch, and while the issue happens less often, it still happens.
The system here is a NanoPi R6S (aarch64) that comes with two rge interfaces on PCI.
The three systems on which I'm seeing this regularly are various amd64 systems running NetBSD 10. Two have rge on the motherboard, and the third on PCIe cards (I tried more than one because I initially thought it might be a bad card).