I am looking for some guidance. My Umbraco backoffice - forms in particular - is missing the generated CSS file …/sb/umbraco-backoffice-css.css.v… It works fine on my local development env. but missing on production env. The prod env. uses the Production Runtime Mode.
In Umbraco 13, in non-debug mode css files and js files get bundled, so you might not see the individual files anymore, so that makes sense. However, I guess it’s not working?
Could also be a cacheing issue.. (locally debug would be true and cacheing would be timestamp - so no minification and compression and minimal cacheing) what setting do you have for runtimeminification for production?
Runtime minification settings | Umbraco CMS
you could test this theory on production by visiting /sb/umbraco-backoffice-css.css.v???? directly and altering the version stamp to see if the content served changes.
Note that not all minification settings are allowed in Production Runtime mode.
See the docs here.. 
Runtime Modes | Umbraco CMS
Umbraco:CMS:RuntimeMinification:CacheBuster is set to a fixed cache buster like Version or AppDomain ;
I normally stick to Version (without specifiy the version as then UmbracoCore generates a hash based around your www project assembly version and the umbraco version… you are incrementing assembly version on each release though??? 
)
@LuukPeters and @mistyn8, thanks for the heads-up. I didn’t have that configured correctly, but I tried the different runtime mode configurations, and I’m still missing the CSS file. The missing styles appear to be isolated to the Umb Forms interface; the rest of the back office looks normal. The compiled js and init CSS file are present on the prod backoffice*
Any information that i need to provide to help further the troubleshooting?