It doesn't mean it is a false positive. The alert in itself isn't what I would call serious "The file is a decompression bomb." I would say it's just damn old.
Based on what I said before, "This used to be a tactic long ago to swamp the system.", which with modern systems with better CPUs and larger Hard drives this is less likely to be an issue.
Selecting every option is I would say overkill, but that's me, there has to be a good reason to do this and your scan time would be greatly slowed.
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With a resident (on-access) scanner the need for on-demand scans is much depreciated as new, opened, modified or moved, etc. would trigger the on-access scanner. For the most part on on-demand scans, dormant/inert files (.zip files, etc.) are being scanned, the other active files are going to be scanned by the resident shields when they are activated.