It has been 47 days since the last Technical Preview of Windows 10 dropped, and at that time Microsoft pledged to speed up the slow preview testing process that occurred between build 9879 and 9926 for future builds, which basically means we won't be expected to wait almost two and a half months between builds anymore.
So far, we haven't seen much of that materialize, despite image leaks of newer builds and lots of information on what we can expect from a newer build, among them being able to test Project Spartan in an either experimental, or somewhat more polished state, for now it's pretty much all guesswork.
However, Gabe Aul took to Twitter to answer questions on when the next build might materialize, and while saying that he wouldn't normally do this, Aul seemed to reveal that just one bug is blocking the build, and that they are "weighing options."
Whether this has to do with the upcoming Insider build or not, is of course, debatable; but it seems unlikely Aul is talking about an internal build for staff testing. Furthermore, when asked directly if we could expect this very soon, or have to wait for a next build: