With what appears to be otherwise very good test numbers, it's hard to know why algae returns, especially MA. Various dynamics could come into play such as localized organic debris, unusual stress on the chlorine at some point, inadequate circulation, or perhaps algae that was undetected and simply resurfaced. Once a regular
SLAM Process is complete, we shouldn't see any visible algae, so all that "might" be left is residual MA spores that require the higher FC level for that 24 hours. But either before you go to MA level, or after the FC falls back down under the regular SLAM FC level, inspect every inch of the pool one more time. Don't forget to remove the drain cover if you have one and check in there. Also behind a light (niche if installed) and hollow ladder or steps. Good luck.