Even if not cleanable, the machine isn't going to actually know if they need to be replaced or not. It will depend on how dirty the air was and how much stuff got filtered out. Normal air purifiers would have a reset option to reset the timer.
The machine can know if it measures differential pressure across the filter. If the DP across the filter is too high (indicating a clogged filter), the filter needs to be replaced.
A machine could, but is this machine sophisticated enough to do that? Why do we play around with hypotethical scenarious where this warning message on another device might not be shitty DRM?
AFAICT, there were no readily obvious DP sensors to be found.