I think there may be an issue with missing EOSEs. Nostur sends a CLOSE after receiving EOSE but for some REQs (not all) on nosflare there is never an EOSE and its probably kept open and hitting the limit of 50, Nostur normally never has that much subscriptions open at the same time.

Example REQ that didn’t receive EOSE:

["REQ", "A4CB2EF4-5DB8-4D74-BF6B-9B860DA44777", {"ids": ["5119271f7af3847dd2c655f6a5cfb1448bb3a70edf52acec4f39844346917cca"], "limit": 500}]