Is there a difference between mobile cache and desktop cache?

As you know, I do many different tests ... Often I find myself in a situation where a mobile test shows low speed, with equal other indicators (FCP, LCP, etc.) and in the same test desktop shows excellent results.
In the second test, mobile results are over 20 points better - and in several tests per minute ...
Ie when online PSI test coincides with "some time recache" mobile results are very low, as if the site has no cache performance ... At the same time test, desktop performance is in comparable excellent condition ...
Is there any built-in difference in cache, mobile and desktop processing?

thanks

No, there is no difference in behavior behind the scenes. We serve the same HTML output, same caches, etc. regardless of the device.

There are minor javascript differences (i.e. there are some areas of javascript that do like "if( mobile ) { do this }") but those instances are minimal. The legwork of the difference in display comes from responsive CSS.