Hello reporting back, perhaps because these forms were created on an older version of CF7, the bug exists. Continuing to investigate. If Takayuki Miyoshi would like the xml file I can provide it in email.
But for now, I will continue to see if I can recreate the issue be recreating the forms from scratch.
After investigating the issue, I have came up with two theories. The first: the contact forms on source.exampledomain.com were all created prior to the import/export feature in CF7. It could be possible the meta is corrupt and the import parser denies the data. The solution would be to recreate the forms.
The second theory is that there might be a character in the meta that is breaking the import parser and it's a parser bug. A special character or a foreign unicode could be breaking the import parser.