Affected versions

• 75.0b3;

Affected platforms

• Windows 8/10; macOS 10.13

Steps to reproduce

1. Launch Firefox
2. Access link;
3. Right click on player & inspect(while it loads);
4. Hover over video autoplay in inspector;
5. Hover back in page (edited);

• in some cases step 4,5 are not needed since the issue manifests as well;

Expected result

• no issues occur;

Actual result

• except the player background nothing else is displayed;

Regression range

• nature of the bug appears to be intermittent, therefor we cannot get an accurate range on this(could not even reproduce on the current nightly);
• confirmed this issue on 3 different workstations but after a while it was hard to reproduce even with fresh profiles / private browsing mode;

Additional notes

• attached recording with the issue;
• tentative section pick, but might not be the root cause.

Spent 40 minutes looking for a regression, but because it is intermittent it is very difficult to determine a regression range.
First bad appears to be in the area of 56.0a1. Don't know if this info is relevant.

Also it is reproducible on Nightly 75.0a1 (2020-02-14).

This happened to me once on macOS 10.13. All I did was to seek forward and backward and refreshing the page. The player suddenly disappeared. Unfortunately, I don't have some solid STR.

It seems a video control issue.

Since this is unlikely to affect non-web developers and is hard to reproduce, I'm setting this as a P5 priority.

@Jaws, just noticed that this issue occurs with Save as option as well.
Updating fields for 80.0b2 and 81.0a1 (2020-08-02).