I tested this on a recent trunk snapshot (2/25), haven't verified with 3.1 or 1.4.1. I can if necessary and update.
Solr is not returning the proper number of facet values when sorting alphabetically, using distributed search, and using a facet.mincount that excludes some of the values in the first facet.limit values.
Easiest explained by example. Sorting alphabetically, the first 20 values for my "subject_facet" field have few documents. 19 facet values have only 1 document associated, and 1 has 2 documents. There are plenty after that have more than 2.
comes back with the expected 20 facet values with >= 2 documents associated.
If I add a shards parameter that points back to itself, the result is different.
comes back with only 1 facet value: the single value in the first 20 that had more than 1 document.
It appears to me that mincount is ignored when doing the original query to the shards, then applied afterwards.
Let me know if you need any more info.