Recently, I've noticed that HTML5 versions of my projects have begun to experience weird graphical issues when scaled up from their original resolutions. Taking a 320x180 game and playing it in a 960x540 embedded window unevenly scales everything despite the perfect 3x scale, and the same uneven pixel scaling applies when doubling a 640x360 game to play within a 1280x720 embedded window. The odd thing is I'm observing this when exporting new HTML builds of older projects where the MFAs haven't been modified at all since their last (unaffected) HTML5 builds were exported - no settings have been changed, the projects haven't been edited in any way. If these glitchy HTML5 builds are played in an embedded window that matches the resolution of the window size as set in their MFA properties, everything is rendered accurately.
Attached are a handful of screengrabs showing what's going on here showing a before-and-after of title screen and gameplay. The uneven scaling is immediately obvious with the font on the title screen's "start" and "how to play" menu buttons. These are captured from an itch.io game page where this particular game is running in a 960x540 embedded window. For thoroughness, I've tried re-uploading the old builds to itch to see if it's something newly introduced on their side causing the uneven scaling, but those old versions render accurately. The issue is only present in newly exported HTML5 builds. Anyone have an idea of what might be going on here?