ASM code D3554 Slow transactions attack detected

We are getting a lot of these messages in /var/log/asm but users report these a valid file upload/download sessions. ASM is causing the upload/download to fail. Is there a way to allow legitimate long transactions, particularly file uploads to continue without ASM blocking them ?

We have understood https://support.f5.com/csp/article/K14199 and increased slow_transaction_timeout to 75 on advice from F5 support.

This fixed the issue for a while, now it's happening again.

any ideas ?