Strange glitch in collab search

I'm betting it's all television series that aren't handled properly.

Clearly The Dick Van Dyke Show (1961) and Mary Tyler Moore (1970) have at least 1 person in common (MTM), but this search comes up empty:
http://www.imdb.com/search/name?roles=tt0054533,tt0065314

This search yielded only their common producer, Norman Lear:
Credited in All in the Family (1971), Maude (1972) 
http://www.imdb.com/search/name?roles=tt0066626,tt0068103
(Maude was a spin-off of AitF, so it's stars definitely appeared in at least 1 episode there.)

Likewise for these, finding only producer Garry Marshall in common:
Credited in Happy Days (1974), Mork & Mindy (1978) 
http://www.imdb.com/search/name?roles=tt0070992,tt0077053
Again, M&M as a spinoff of HD. Guaranteed common cast.

Nothing in common for this parent & spinoff:
Credited in Cheers (1982), Frasier (1993) 
http://www.imdb.com/search/name?roles=tt0083399,tt0106004

So the search is not digging down to episode-level data? Or cast data?

Did developers misunderstand a prior bug report about NAME collaborations (which are finding TV series in common between 2 people, but not identifying the episode, and they were NOT in an episode together?) And instead now they've restricted TITLE collaborations to some inappropriate higher level of search? (The bugs are really sort of inside out of each other.)

Example:
Most Popular Titles With Reginald Owen And Reginald Gardiner
http://www.imdb.com/search/title?roles=nm0654239,nm0306786
includes  Bewitched (1964–1972)
Reginald Owen is in 2 Episodes: 
- Mc Tavish (1968) ... Ockie
- The Short Happy Circuit of Aunt Clara (1966) ... Ocky
Reginald Gardiner is in 1:
- I Get Your Nannie, You Get My Goat (1967) ... Lord Clive Montdrako

Being in different episodes would not satisfy my definition of collaboration.