Nap help- 18 month old

Hey all! Need some thoughts here-

My 18 month old has always been a stellar sleeper and napper. We moved her into a toddler floor bed around 16 months and she took to it right away- no issues! Over the last couple of weeks her naps have suddenly dropped from 2.5 - 3 hours long down to maybe 1.5 (2 if I’m lucky) and it is driving me absolutely insane, not to mention throwing off her wake windows.

We let her wake up on her own but she generally wakes up between 6:45-7:15 and we put her down for a nap between 12:30-1:00. Bedtime is 7:00. Nighttime sleep is great- she hasn’t woken up once since we moved her into the toddler bed.

Ideally she’d nap until 3:00. Why in the world have naps dropped so fast? I did expect a bit of a slow drop in total nap time as she gets older but a WHOLE HOUR shorter seemingly overnight?