Yeah, I think last year had a couple of "special" clipshow episodes, as well. To be fair, US shows often take a break for a week, only they usually show a repeat instead of a "special" clipshow. But the principle is probably the same, there might be some holiday, or some big television event that they don't want to air a new episode against.
Sure, but it's weird to have it happen when the show's only a month old. I guess maybe it's to avoid the Olympics or something. Kamen Rider and Super Sentai took a week off too, but it was a week or two before this.
And here is episode #4 of "Ultraman":
This one actually was a sequel to "Ultra Q" episode #20, establishing the two shows as being in the same universe.
Despite having the same female lead playing a totally different character, as well as other regulars from one show playing guest characters in the other. And the last episode of Ultra Q was delayed, so that it actually aired during Ultraman's run. That must've confused the kids.
According to the Wiki, apparently Ultraman was originally meant to be 20 years in the future, with the SSSP organization having been founded by Ultra Q's recurring scientist character some years after that series, but it was later retconned as having taken place in 1966-7, the same time it aired. A lot like the UNIT dating controversy in Doctor Who.