Unable to Retry and Undo & Exit

Retry and Undo & Exit buttons visibly depress as normal when clicked, but do nothing.

Update: Issue occurs when i have left the container out of physics range without delivering it.

i have no clue how to recreate it, i think i first encountered it doing an Ocean Delivery and Hippolyta Ground Station delivery mission at the same time, but i had done extensive testing before i set off for the missions with the payloads on board. this was the second or third attempt before the bug, and i had reset the mission to time warp ahead so my destination would be in sunlight then (frustratingly) having to load a seperate craft without payloads on board to allow time warp. it was after i saved that flight and recovered it that the next payload testing flight was un-undoable, the buttons did nothing.

itermittent error, no common thread, might be from accidentally dragging the menu when clicking the buttion, my mouse ghost clicking it weirdly, or related to electic motor propellors or large payloads detached from side interstages? happens on short and long test flights, and has caused payloads to go missing despite me causing a forced mission revert by force quitting the game.

i use a few mods, including one technically unsupported one, but issue persists with them disabled.
i have had the game for a long time, and have migrated the install between computers.
this bug is quite urgent, it makes the game functionally unplayable for me because i'm not an expert about what will work without testing, and i often make mistakes during flight or run into uncontrollable scenarios because of design oversights.