https://www.congress.gov/img/member/https:/congress.gov/img/member/e000198_200.jpg%3c/ImageUrl
I see it at this endpoint:
https://api.congress.gov/v3/member/?format=json&api_key=INSERT_KEY
as well as the individual member endpoints, like:
https://api.congress.gov/v3/member/F000062?format=json&api_key=INSERT_KEY
It looks like only 6 are affected, with updateDates between 2023-09-19T19:40:26Z and 2023-09-29T13:24:39Z. Note that there was one member who was updated during that time period who wasn’t affected.
Users noticed that several of the members available via [https://api.congress.gov/v3/member/?format=json] have repeating text in their imageUrl.
Example: