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Dis-assembly and Cleaning is the best option which will affirm if there is etching into the glass.
Etched glass is not necessarily bad depending on what element it is. I think Macros would make the presence of fungi/etching more obvious than others, but I could be wrong.
Cleaning should involve not just the affected glass but the entire lens (all optics and the barrel) to get rid of any spores so that there is no recurrence.
Fungal spores can be viable for a very long period even under unfavorable conditions. If there are still any spores lying around after cleaning there could be a recurrence. So mere cleaning may not enough (unless it was a very thorough job). It's best to watch for any recurrence. Recurrence may not necessarily be bad as long as it is dealt with in a timely manner as fungi are most susceptible in their hyphal stage. So if measures are taken (light and humidity control) immediately after a recurrence, then the chances of preventing further outbreaks are much better and the lens could be saved.