It's being interpreted as an IP address. It shouldn't do that if you use commas instead.
Summit
Community to discuss Summit, a Lemmy reader for Android.
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Sounds like a design oversight in the app. Probably worth reporting it as a bug.
In parts of the world, long numbers are separated using commas. In other parts, they use periods. You clearly use periods.
The app probably auto converts long period-segmented character strings into urls for user convenience. However, that interferes with users like you who post numbers.
I'm not really sure there is a satisfying answer here other than making a setting for it. If I disable this feature outright then ip addresses will not show up as links. If I enable it then you get the issue you see. In either case I would assume that this is a pretty rare case. I'll add it to the road map.