As seen on https://en.wikipedia.beta.wmflabs.org/wiki/T355999 the input $\sin \log_a$ generates
<mi>sin</mi> <mo>?</mo> <msub> <mi>log</mi> <mo>?</mo> <!-- This element should not be here--> <mrow data-mjx-texclass="ORD"><mi>b</mi></mrow></msub>
However, the mo should not be generated or generated after the msub element
This was introduced in https://gerrit.wikimedia.org/r/c/mediawiki/extensions/Math/+/987176 styleargs should be passed but not foundNamedFct
Change 1002631 had a related patch set uploaded (by Physikerwelt; author: Physikerwelt):
[mediawiki/extensions/Math@master] Only pass stylearg state variable to base of dq elements
https://gerrit.wikimedia.org/r/1002631
Change 1002631 merged by jenkins-bot: