Reproduction steps:
1. Create and open a new Unity project
2. Import the attached "ProblematicModel.fbx" model

Expected result: it takes around 5 seconds to import the model (depending on the machine used)
Actual result: it takes over 16 seconds to import the model (depending on the machine used)

Reproducible with: 2020.1.0a19, 2020.1.1f1, 2020.2.0a19
Not reproducible with: 2018.4.25f1, 2019.4.5f1, 2020.1.0a18

Notes:
-The time values are taken from the Editor.log file
-The speed of importing only Animation files to the Editor doesn't seem to change across different Unity version and is consistently good. The problem only reproduces with an fbx file containing Animations.
-The import time is consistently around 3 times longer in the affected versions