Since size of files are somewhat a limiting factor in sending samples over, the videos behind the links (offered by “WeTransfer”, as you suggested) are excerpts of about 30 sec (~30Mb).
Two sets are being sent for your perusal. Under each link there is a source-sample (in 3 parts, as is generated by the devices at recording) and 2 “manipulated” results: one with 2.6.21 version and another with 2.7._the_latest. [Manipulation here was practically limited to loading & saving – with testing the stepping-keys, too.]
1.) from News M1-hu media:
https://we.tl/Cne2XFzKzq2.) from a film:
https://we.tl/16PnRTLrPG The “Av 2-6_manip” files clearly show the flashing-effect.
While as to the Avidemux 2.7. I have to correct my previous statement. All that was said stood for an earlier 2.7. version. [Which, however, has been overwritten on refreshing it with the latest (e.g.: 2.7.0r180405_win64.exe).] That is, this latest 2.7. version gives free-of-flashing results.
HOWEVER:
• On loading the source-video you can discern that while the “1 minute” and “the smallest” steps (back&forth) are functioning proper, neither the “medium-stepping” nor dragging-on-timeline works as they should: the screen is gray-blank – just as it is right after loading.
• Another big difference exists in loading: This latest version do not offer concatenation of sequential files while all previous versions did. [And since recording TV-broadcasts (at least in my arrangement) is done by breaking the film’s content into 1GB portions (separated by those 64kb service-files), such an option back would be a welcome.]
These side-effects together make fine-manipulations quite tedious, especially when problem appears at saving (marked as “Video is too short/incomplete”) due to unhappy gaps under recording, and the erroneous part to be dropped is to be searched for by fine-tuning.