User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

Tested on Debian 10 with Firefox 69 on a new profile.

Created web page with two input fields of type "time".

1 - The first one is disabled with the "disabled" HTML attribute

<input type="time" value="00:00" disabled>

2 - The second one is disabled with JavaScript

<input type="time" value="00:00">
<script>
window.onload = function() {
  document.querySelector("input[type=time]:not(:disabled)").disabled = true;
}
</script>

Actual results:

The first input field, disabled with HTML attribute, has a dark reset button.

The second input field, disabled with JavaScript, has a lighter reset button.

Expected results:

I expected the reset button color to be the same for both fields.

I can reproduce this issue on both Windows 10 and Ubuntu 16.04, with similar results as reported with 69.0 2019-08-27.

Investigating further, seems like the bug gets fixed in 70 and 71. (70b3 2019-09-02 / 71 2019-09-08)

Mozregression shows this issue is fixed by 1519958 in Fx70+.

Note:
Also attaching the testcase I forgot to add earlier on.

(In reply to Adrian Florinescu [:adrian_sv] from comment #2)

Created attachment 9091391 [details]
time.html

Mozregression shows this issue is fixed by 1519958 in Fx70+.

That doesn't seem like a plausible fix. I think this is actually a dupe of bug 1561787.