luigidelgado, in your case I really don't know and can't even reproduce your environment. My recent idea was in completely different direction, it's not your case. Already tested it, didn't worked (
Regarding how I fixed this WSOD for my website - I actually managed to make it work fine with CDN. Disabled it just because it's too slow for my region (local ukrainian and russian traffic). CDN wasn't causing that WSODs. Turn off all caches one by one. Than turn them back on one by one, but, as soon as you check the "Page Cache" checkbox, BEFORE saving settings scroll down to DEBUG section and uncheck everything (the first checkbox is being turned on by default, as I noticed). Then save settings and countinue turning on all other caching methods you use. After that clear and rebuil all caches. It worked in my case, tried this several times. Restored DEBUG, got those WSODs again, repeated described steps - and everything is working again.