Yes of course, but I would expect many commits between stable releases (patching issues). I guess this is just a different pattern where a solo-dev goes quitely working for a few months and then emerges with the next release.
To give some context, even though the version is at 0.2.x, it's been fairly stable for months, and there have been very few bug reports (despite it being used fairly extensively in relatively big codebases - see lichess.org, for example).
Most of the "bugs" (or rather, limitations) in the issue tracker are either discussions or things that are difficult to address w/ the current codebase - e.g. design/ergonomics issues, as opposed to implementation issues - Those are part of the reason for the rewrite.
Another thing that is worth mentioning is that Mithril's general philosophy is to avoid adding features for features' sake, so it can look less "active" than it actually is.
