I don't know the exact reason why, but it probably has to do with the fact that Edge and Firefox both use Direct2D for rendering and DirectWrite for text, while Chrome uses Skia (which can call into DirectWrite or GDI for text rendering I believe, but may not do so in the exact same way).
What does that actually means in practice? I'm guessing the only time you actually get skia is when running in a pretty old hypervisor environment or on a server/BMC without hardware acceleration.
Which IMHO, having your application _LOOK_ different depending on hardware acceleration capabilities is sorta stupid.