Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: Radeon Pro 580 ATI Technologies Inc. 4.5.13476 Core Profile Context 18.104.22.1686
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-02 22:33, hash: rB50ccbe6bb233
Short description of error
Tail bone locations seem to be incorrect at the end of chains or when other bones are parented mid bone.
Exact steps for others to reproduce the error
See the attached Blend file, export the 'Export' collection as an FBX. Try with Tail bones on and off.