ID 441169 - [C] Markers: Altering the duration of a panel that has a Marker will often cause the start points of the two to no longer match

Problem summary
Marker start point in time no longer matches that of the panel it is on, once that panel's duration is altered.

Customer reported version
Flix 6.3.2

Steps to reproduce

Note: This bug does not reproduce immediately

1) In a clean Sequence Revision, import 4 panels and don't alter their duration. Default for panels in Flix is 12 frames each.

2) Put a Marker on the first, and one on the third panel. The Markers start points will be respectively 0, and 24.

3) Go to View > Dev Tools. 

4) With the Dev Tools open on the right, change the first and/or the third panel's duration.

5) Save the Revision, and check the revision request in the Network tab of the Dev Tools, under meta_data to see if the Markers start points are still matching the starting points of the panels they're on.

6) If the bug hasn't reproduced, repeat points 4 and 5 until it does.

Expected behaviour
The start points in time for the Marker and the panel it is on still match.

Actual behaviour
The start points no longer match

Reproduced by support

This bug has been reproduced in:
6.3.3 - macOS 10.14.16 Client