I was having the same issue.,
OTS parsing error: Failed to convert WOFF 2.0 font to SFNT
(index):1 Failed to decode downloaded font: http://dev.xyz/themes/custom/xyz_theme/fonts/xyz_rock/rocksansbold/Rock-SansBold.woff2
If you got this error message while trying to commit your font then it is an issue with .gitattributes
"warning: CRLF will be replaced by LF
"
The solution for this is adding whichever font you are getting the issue with in .gitattributes
*.ttf -text diff
*.eot -text diff
*.woff -text diff
*.woff2 -text diff
Then I deleted corrupt font files and reapplied the new font files and is working great.