Hi, not sure if this is a correct place to leave this bug report.
I'm playing FeedTheBeast Direwolf20 1.7.10 modpack, which includes Buildcraft 6.2.6 and Thermal Expansion 4.0.0B8-23. Here's gist with all mods list.
I don't know if it is a thermal expansions bug with tesseracts, but fluid pipes simply do not connect to them in any configuration. Kinesis and item pipes do work correctly. Please, see attached screenshots.

Is this a Buildcraft bug or should I go to thermal expansions issue tracker and make them a little bit happier? :)

I think fixed on both sides, but DW20 is so slow at updating

OK, thx a lot! :)
I've updated buildcraft manually and it works like a charm.