Esxi running macos For selur

[Selur]

Collect keyframes. Different length, difference is really huge. Is this normal like this?

Without seeing a debug output, knowning the source format and it's characteristics: no clue
Might be some bug. Does not happen when loading MPEG-4 based formats here.
Wild speculation: if the input is vfr strange things might happen.

Collect keyframes + Frame Selection. Show different number of frames.

That is the logical follow-up of the one before. Since using 'Collect key frames' changed the length, naturally it also changes the frame count.

Always + Frame Selection. "start" text field changes to dropbox button and i can not change it anymore. Is this a bug?

Did you bother to read the tool-tip of the 'always' option?
It enforces key-frame based cutting, so naturally your cut can only start at the times of key-frames.

Cu Selur