Hmm, so the slowdown is occurring when tyFlow is just updating the Phoenix object (calling Phoenix's own functions). The actual work being done in the Birth Fluid operator is not the cause of the slowdown.
To further debug this I would need access to the cache and your scene. If you want to zip it up and send it over to support@tyflow.com I can see if there are any other clues that might explain what's going on.
To further debug this I would need access to the cache and your scene. If you want to zip it up and send it over to support@tyflow.com I can see if there are any other clues that might explain what's going on.