Based on this question.
Illusory reality (PHB p. 118)
When you cast an illusion spell of 1st level or higher, you can choose one inanimate, nonmagical object that is part of the illusion and make that object real. You can do this on your turn as a bonus action while the spell is ongoing.
The feature is meant to be read in its entirety, which talks about one object. The bonus-action sentence doesn't undo that.
Illusory Reality is intended to make one illusory object real per illusion spell.
Is the intent that the Illusory reality feature can be used only once per spell, or is it allowed to be used multiple times per spell, but only for one (the same) object, effectively allowing you to refresh the duration on that object?
As an example, can you make real an object, and as the 1 minute duration of illusory reality expires, refresh the feature on the same object? Can you do this while the first use of Illusory reality has not expired yet?