Empty messages dated 1/1/1970 01:00
On first start of Thunderbird in the unified inbox there are sometimes empty messages listed with date of 1/1/1970 01:00.
When I click on any of them to view message, they always just blank empty body with no subject or sender. If I click on any other inbox, then go straight back to the unified inbox, the blank messages have gone.
I recently upgraded from v140-ESR to v147-Release and thought it may stop happening, but it still occurs sometimes.
Doesn't seem to be doing any harm but it's strange behaviour nonetheless, so thought I'd see if anyone else has experienced this or what you guys think could be causing it.