I reproduced this issue using Fx 65.0a1 (2018-02-19), on Windows 10 x64. I can confirm this issue is fixed, I verified using Fx 66.0b7, on Windows 10 x64, macOS 10.13 and Ubuntu 14.04 LTS.
Bug 1512481 Comment 12 Edit History
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I reproduced this issue using Fx 65.0a1 (2018-02-19), on Windows 10 x64. I can confirm this issue is fixed, I verified using Fx 66.0b9, on Windows 10 x64, macOS 10.13 and Ubuntu 14.04 LTS.