A serviceability enhancement in HCX, to identify the condition and fail the initial validation for the migration workflow, has been implemented in service update R145. Upgrade to that version or later is required.
The user is still expected to correct the vmdk size issue.
Refer to instructions in the workaround section.
Workaround:
Abort the stalled migration and follow the recommendation in KB
2061047 prior to attempting the migration again.