Since I have installed the IDE 1.8.10 this message comes with correct compile too.This irritates (see many posts in the past) and should be corrected. There is really only one library present.
Example (after correct compiling):
Multiple libraries were found for "SeedLidar.h"
Used: D:\Arduino\libraries\SeedLidar
Multiple libraries were found for "Serial115200.h"
Used: D:\Arduino\libraries\Serial115200
Using library SeedLidar in folder: D:\Arduino\libraries\SeedLidar (legacy)
Using library Serial115200 in folder: D:\Arduino\libraries\Serial115200 (legacy)
Common problem and not just 1.8.10.
Just ignore it.
The IDE is getting very buggy now with simply crashing out, multiple instances of the same COMs port and "cant find file" on compiling after a few day's use.
Just make sure you save work frequently and don't expect it to be working 24-hrs later.
My gut feeling is that it just runs out of resources and gives up.
From my feeling: some hundreds of users has problems with this annoying mistake!
The moderators can give over and over the same hint: ignore it.
And in the future further hundreds users will run into this small pitfall. This should be a reason for an update!
There have also been occasions in the past where a particular IDE version has its own set of issues prompting the stock answer of "roll back please"
Throwing mud at moderators is a fruitless point.
Almost all of us "do not work for Arduino" and are often just Arduino users like yourself with no pay or real benefits from the task just a sense that we try to keep the forum running as smooth as we can with the aid of so many decent users who also see what we can often miss.
You nailed it quite well with "small pitfall" and until the next version does come out ( as they always do ) the "roll back" advice is the best there is unless you are able to identify and fix a particular issue.
If you can fix an issue then the best place to deal with that is on GITHUB where it will stand the best chance of being implemented.