Yahoo emails "No Sender/No Subject"

Over the last couple of months, I often see emails from Yahoo that say "No Sender" "No Subject" and "This Message has no Content" with a date of 12-31-69. It first started happening at the same time as an unrelated issue where Yahoo was having server issues of some sort. I removed and readded the account but this other issue with ghost emails has continued to occur, more frequently, as a matter of fact. This only occurs with Yahoo on both my iPhone and iPad; I have iCloud and an Exchange account and those don't have those ghost emails. Yahoo and Apple have both said to contact the other.