Ok, think we found the culprit - the qfle3-1.0.60.3 driver.
We ended up installing a driver upgrade to qfle3-1.0.60.4 (the host was on 1.0.60.3). After applying driver upgrade, I am no longer seeing the loss of network connectivity behavior after testing vmotion multiple times.
I opened up an HPE support case questioning this driver version and if this is a known issue as its included in their latest HP Custom ESXi 6.5 update 2 ISO.