instaloader: One account can't find any profiles anymore, another can

Hey all, I have two test accounts. One test account can successfully download anything - other comes up with the following (tested against the same profile), even when it’s a profile I’ve been able to download from that account before (or, a public profile):

$ instaloader --login=USERNAME --sessionfile=.insta-session --fast-update PROFILE
Loaded session from .insta-session.
Logged in as USERNAME.
Trying to find profile PROFILE using its unique ID 112233445566.
Profile PROFILE has changed its name to PROFILE. #lists the same name in both fields here
Profile PROFILE does not exist.
Trying again anonymously, helps in case you are just blocked.
Warning: PROFILE will be downloaded anonymously (Profile PROFILE does not exist.).
Downloading anonymously: PROFILE
PROFILE/2019-07-07_07-23-32_UTC_profile_pic.jpg already exists
Retrieving posts from profile PROFILE.
[  1/ 18] PROFILE/2019-07-25_21-38-09_UTC_1.jpg exists PROFILE/2019-07-25_21-38-09_UTC_2.jpg exists PROFILE/2019-07-25_21-38-09_UTC_3.jpg exists PROFILE/2019-07-25_21-38-09_UTC_4.jpg exists [Caption…] unchanged json
Saved session to .insta-session.

Errors occured:
Warning: PROFILE will be downloaded anonymously (Profile PROFILE does not exist.).

Nothing updates successfully, even when dropping the session file off and starting from scratch. Any clues?