I can continue for a long time but these are the main reasons.
How to understand why lashes still fall off? You need to figure out HOW they fall off:
✔️ with or without natural lashes
✔️ how fast and their quantity
If the lashes fall off during the first days (1-3 days) after the procedure, mainly without natural lashes, then we should look for a reason. If the client loses 2-5 lashes per day from both eyes and mainly with their own, then this is the norm. It's the usual process of life of native lashes.