The algorithm looks at the increase in light with the laser on compared to the laser off. If ambient light is very bright then laser can’t contribute much additionally and reflection is determined as low.
Anyway, to confirm that the issue is related to the ambient light, let’s look at the reflection rate as day progresses.
The reason that this wasn’t an issue before could be to do with the weather (e.g. cloudy day) and seasonal sun altitude.
There are ways to lessen the effect of the ambient light described in this post.