Dealing with fluid dynamics and material handling is not as...

Dealing with fluid dynamics and material handling is not as simple as that, unfortunately.

Some things are "simply" scaled and some things are not. Ponder things like pressure, flow rate, filter sizes, just for starters. Then consider the circuits pre and post filtration, and the integration etc.

Also consider that there is also a step from batch (or "more batch" ) to continuous (or '"more continuous" ) plant operation; this may (and apparently did) identify unforeseen issues with filtration performance and what appears to be some material handling/clearance/flow issue.

One may be tempted to argue that if they had a 500tpa filtration circuit "fully sorted" in the pilot plant, then why not replicate x4 and hit the green button.... but afaik the pilot plant wasn't set up to run "continuously" and therefore the recent issues weren't readily identifiable from that earlier work. Also a simple x4 may not integrate well into adjacent circuits.

As frustrating as the delays are with the current plant, imo it's important to recognise that it was effectively impossible to eliminate ALL scaling risks using the pilot plant. Unfortunately we hit a snag with the filtration circuit and are working through the process to rectify it.
I'm glad it's nothing to do with the core chemical process, which has indeed proven scalable and successful.

It sucks, sure, but nothing we can do but let the engineers work through it, and of course learn something for next time.