If you are seeing this at startup, it is normal. Ignore it.
I'm sure there is some technical explanation, but I have *always* seen this, and recall there was some explanation from Motorola with advice to ignore. You might search the forum.
If you are seeing it other than at startup, I might be concerned.
I think it should actually be interpreted as "thread queue has been blocked", not "will be blocked". I don't see how it is possible to know how long the thread queue will be blocked. If you could do that, it could make you very, very wealthy.