What does the full Ditto call look like? Presumably it must include at least &paginate=`1` if you are getting pagination sometimes.
Have you tried adding &debug=`1` to see what parameters Ditto is actually using and what it is retrieving?
Caching is fairly simple: if you don’t have the full PHx plugin installed, make the Ditto called [!uncached!] and the document cacheable; if you do have PHx plugin, make Ditto call [[cached]] and document uncacheable. Caching factors affect debug the same way as they affect pagination - the debug console doesn’t work if the caching is wrong.
:) KP