http://freedb.musicbrainz.org/~cddb/cddb.cgi?cmd=cddb+query+e810c510+16+150+17320+50665+73190+89172+102267+130270+151510+168462+189452+204012+228737+250427+269637+282100+298625+4295&hello=mail+mail.com+"test"1&proto=6
returns
"rock 001064da soul classics / Tutti! Orchestral Sampler"

while the CDDB id is really e810c510. This is likely caused by offsets being slightly off:
http://freedb.musicbrainz.org/~cddb/cddb.cgi?cmd=cddb+read+rock+001064da&hello=mail+mail.com+%22test%221&proto=6
(e.g. second 17325 instead of 17320)

Also, I don't get where the "soul classics" (instead of "Various") comes from...

This seems to happen to all disc ids, not just the example above, e.g.
http://freedb.musicbrainz.org/~cddb/cddb.cgi?cmd=cddb+query+a90bc50c+12+150+21505+37850+52195+76612+96457+123527+138815+153465+170895+187217+204467+3015&hello=mail+mail.com+%22test%221&proto=6