Incorrectly parsing overfull hbox as error under certain conditions

[wilbowma]

I have a file that latexrun is detecting errors in, but when I compile manually and inspect the log, there are no errors (although plenty of warnings particularly overfull hboxes).

I believe this is caused by the following warning in the log:

Overfull \hbox (83.6969pt too wide) in paragraph at lines 582--583
[]\T1/LinuxLibertineT-TLF/m/n/10 (-20) We want to show that $\OML/nxlmi/m/it/10
 embed[]\LMS/ntxsy/m/n/10 <B9>\OML/nxlmi/m/it/10 C\LMS/ntxsy/m/n/10 <BA> ` [][]\OML/n
xlmi/m/it/10 i \OT1/LinuxLibertineT-TLF/m/n/10 (-20) : \LMS/ntxsy/m/n/10 <B9>[][] 
\OML/nxlmi/m/it/10 ^K[]\LMS/ntxsy/m/n/10 <BA>[]<B9>[] \OML/nxlmi/m/it/10 ^K\LMS/ntxsy/m
/n/10 <BA>[][]\U/ntxmia/m/it/10 ^^@[][]\OML/nxlmi/m/it/10 ^^^[] \LMS/ntxsy/m/n/10 
! <B9>[][] <B9><BA> \OML/nxlmi/m/it/10 ^K[]\LMS/ntxsy/m/n/10 <BA>[]<B9>[] \OML/nxlmi/m/it/10 ^K\
LMS/ntxsy/m/n/10 <BA>[][]\U/ntxmia/m/it/10 ^^@\OML/nxlmi/m/it/10 ; \LMS/ntxsy/m/n/
10 <B9>[][] <B9><BA> \OML/nxlmi/m/it/10 ^K[]\LMS/ntxsy/m/n/10 <BA>[]\OML/nxlmi/m/it/10 ^^^[]
$\T1/LinuxLibertineT-TLF/m/n/10 (-20) . 

Notably, the warning message contains an ! at the beginning of a new line, due to line wrapping. However, it's a false positive, as that is part of warning, not an error.