6.1.6 - USB data corruption

[sd_tom]

Host: Windows10,
Vbox 6.1.6
Guest CentOS7 + 6.1.6 Guest Additions, 6.1.6 Expansion Pack
USB Controller - xHCI

This was an upgrade to an existing image that was running:
- VBox 6.1.4
- 6.1.5 - Test Image Guest Additions (upgraded because clipboard was broken)
- 6.1.4 extension back

Prior to upgrade, was able to do 1000000 baud rate transfers (yes, I know this is an oddball baud rate) between a nordic pca10040 (dev kit) and guest OS, which shows up as FTDI FT232R to VirtualBox. After upgrading, some packets are failing CRC checks. If I use the host PC to do the same transfer, it still works.

Full topology
Nordic PC10040 -> 'Plugable USB 3.0 Docking Station' -> Windows 10 Dell Laptop -> Virtual Box -> CentOS 7

Of note, I was having USB flakiness (similar but couldn't say for sure if the same) when using the USB 2.0 (OHCI + EHCI) Controller back on 6.1.4, but switching to the expansion pack controller resolved it at the time.

Anyways, I did notice in the change log the USB driver was touched so. Can I downgrade back to my old setup easily? Figure that is a good debug step anyway.