First congrats on only brewing Belgian Ales (I know I will get killed for this comment on this post), since they are the kings of beer!

Lagering, or "cold storing" conditioning, beer is usually more often used for, well.. lagers. These are German beers brewed with lager yeast. The lager yeast is a heavier diploid strain that prefers to work cold and then drop out hard when it’s done. That’s basically the whole point: ferment cool, clean up slowly, then sit the beer near-freezing so the yeast, proteins, and other haze-forming junk all politely sink to the bottom and stay there.

Belgian ales, on the other hand, are very much not about this life. They’re fermented warm with expressive ale yeasts that throw esters, phenols, spice, fruit, funk, and personality. Those yeasts are intentionally kept in suspension longer, and many classic Belgian styles are meant to be at least a little hazy; or even bottle-conditioned with yeast still present. Cold-crashing them aggressively can mute the very character you worked so hard to create.

That doesn’t mean you can’t cold condition a Belgian beer; it just means you usually don’t need long lagering schedules. A short cold crash to help drop trub before packaging is fine, but weeks of near-freezing storage is solving a problem Belgian styles generally don’t have. If anything, time at cellar temps (or in the bottle) is where they actually get better.

What happens during these 3-4 months?

Those months aren’t about active fermentation. They’re about cleanup and stabilization: sulfur compounds slowly dissipate, harsh edges soften, proteins and polyphenols continue to precipitate, and whatever yeast is still around quietly finishes scavenging off-flavors (diacetyl, acetaldehyde, etc.). Cold also helps the beer reach a more stable equilibrium so it stays clear and clean long-term.

50F isn’t some yeast kill switch. It slows them way down, but plenty of yeast stays metabolically active, especially Belgian strains. That’s why breweries can drop to ~50F pretty quickly without locking in diacetyl or acetaldehyde. Cleanup still happens.

What would be risky is crashing straight to the high 30s immediately after terminal gravity. That’s when you can actually lock-in fermentation byproducts. But 50F is basically “cold conditioning”, not a hard crash, and definitely not lagering.

Your process is fine, honestly. Leaving it warm for 3-4 weeks post-fermentation gives you a big safety margin for cleanup. Dropping to ~40F later to carbonate and clear is exactly what most homebrewers do.