I’ve been getting some strange font rendering only on Kinopio and only when using a particular monitor. The scaling factor on mac also has to be set to a non-integer multiple of the default scaling one. (i.e. the default times 2 is crisp but between 1x and 2x is not.)
I’ve been using Firefox. I’ll comment back with how chrome looks when I get back to the monitor.
what monitor and resolution scaling factor are you using (I’m guessing you set up your resolution through the normal macos display preference?)
Sorry just now got back to the monitor:
I’m using a Dell U2723QE with resolution set to “Looks like 2560 x 1440”.
It does seem better today, though. I’ll let you know if I see it again!
Thanks for reporting.
I’ve noticed this on my built-in MacBook Pro screen at times, but it was the whole screen—not specific to Kinopio.
I just watched your video again. I agree, weird! It’s very interesting that it shows up in a recording. I don’t know how the rendering stack works, but this tells us something about where the problem is/isn’t 
Sadly this is still causing issues for me when I use a monitor…
either in the webconsole or with a userscript, can you try applying any of these css web font overrides font-smooth - CSS: Cascading Style Sheets | MDN to either the * element or to .cards to see whether that changes things?
I tried the firefox version: -moz-osx-font-smoothing with various values, with no luck.
But! I did find out that when the page size is under 2048 pixels wide (with window.innerWidth) then I don’t have any flicking or blurriness. Super weird! But that will be plenty wide for me, so all good for now. Thank you!
Glad you figured it out 
Here’s the display settings: