This has happened to me more than once. In other words, I am 100 % positive that the above change occurs even though it is not frequent. I post this hoping that a site administrator who is involved with the issue takes note.
...for that purpose, please submit a Support Request, as indicated in the FAQ:
10. How can I contact ProZ.com staff?
The quickest, most convenient (and most highly preferred by ProZ.com staff) way to contact ProZ.com is to submit a:Support Request
Comments and suggestions, as well as reports of problems and requests for help should be submitted using the Support Requests link above.
Note: Most system messages come from firstname.lastname@example.org.
This is NOT a valid address, and any replies are automatically deleted. Please submit a Support Request instead.