Hmmm I’m not sure about this, so take my answer for what it is (pure hypothesis):

Time ago (with old PC) I had similar issues. Then when AoS chapter 3 came out, it became basically impossible to play and I had to install CE on the SSD (I kept it on HDD until then).

After that I was able to play, but still had these teleporting issues.
Now with a new PC (a gaming PC - 2000€ budget) I don’t have those issues anymore.

Since you said your wife’s PC has lower specs than yours and this happens to her only, I think it may be due to that.

But, again, this is pure hypothesis.