No, the A in the fourth beat of bar 1 maintains its End voice property, but since it is now a blue voice, it is “ending” the blue voice: as you can see from bar two the bar rests are now green. It means that the blue rest are (as expected) removed, until the blue C “restarts” the blue voice in bar 5.
So if you change the voice of a note with End voice property active, the End voice property (which his now belonging to a new voice) will also change which voice it influences.
But if you have more music in the (now) empty bars, and you have there a note in the green voice, when you remove the rest in bar 5, the last note of the green voice (for example in bar 4) will have an End voice property, so changing the voice in notes of bar 1 will not influence the rest in bar 5.
To avoid losing the rest, you may want to set following Notation Options/Rests (maybe temporarily):
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Bar rests in additional voices: Show bar rests
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Coincident rests of the same duration in opposing voices: Show every rest in each voice
This allows the rests of all voices to remain visible. Doing so, removing the quarter rest in bar 5 will give the End Voice property to the last rest (or note if present) of the green voice in bar 4 (and the Start voice will be given to the first note after the removed rest). So if you now change the voice of the green A in the first bar, bar 5 will remain unchanged:
Here a short video: