This has happened to me and my wife. BUT NOT right away. Our new save is on a switch and we play local Here is the order of what we did:
1. We made a new farm after we got the update.
2. We played to Day 24 (Flower Dance).
3. The night prior I used a book and received power
4. Woke up on 24th and its lagging for both of us but only on the farm.
5. I turned off wifi completely and ran the game solo on regular play. Still lagging.
6. I slept through the night and now the lag moved to inside the players home. But no longer effects the farm.
extra notes:
A. I ended up deleting this note and too lazy to undo the A.B.C’s lol
B. 3 seconds of play = about half a second of lag. Only on the Farm at first.
C. It’s not a wifi issue.
D. Switch is Updated
E. When on local it affects both people playing.
F. Deleted the game and redownloaded - no effect
G. On The New Farm and Other Farms
H. Lagged area sometimes moves after saving. ( Might start in farm, after save, next day it’s in the house but now farm not effected).
I. Happens to those on older saves as well