If you commit an update set, only the changes with in that update set will be applied to that particular instance. if any features /components missing it will give a warning/error messages while previewing the update set. SNOW has the capability of recognizing missing features in any uncommitted updates sets and give a message like -- more recent updates of this activity in an uncommitted update set. you can skip or accept the remote updates.

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PS: Please hit like/helpful...if it helps.