DeepSeek v4.1 Flash: session throttles after ~13 minutes, new session works fine simultaneously

[alexander-alex-roy]

Description

DeepSeek v4.1 Flash sessions start throttling after roughly 13 minutes of use. The session becomes progressively slower until it barely responds, making it effectively unusable in the middle of a session.

Steps to reproduce

1. Start a session with DeepSeek v4.1 Flash
2. Use it normally for ~13 minutes
3. Responses become extremely slow — barely responding
4. The session stays unusable from that point on

Evidence this is not a server issue

While the throttled session is struggling, I can create a new session at the same time and it works just fine for about 10 minutes (presumably until it hits the same wall). If this were a server/load problem, new sessions would be equally affected.

Question

Is this intentional throttling after a session-duration limit, or a bug? If it's intentional, it's very scummy behavior — silently degrading a session instead of telling the user. If it's not intentional, please look into it.

[Mandi-Sa]

Yes, I've noticed this issue too—as the session duration increases, the responses become progressively slower until it takes about 2 minutes for the first token to appear. Perhaps "freebuff" is indeed a way to reduce free token usage, who knows.