Strangely enough, yesterday was the first day in a long time I have not seen any hybrid trains on the line. There were many Type 8's (I was in one), a couple of Type 7's and a couple of LRV's, but no t7+t8 consists. So not only have I not seen the third modified t7 - I haven't seen any in the past few days. Maybe it's in testing.
BTW, the modifications, unfortunately, do not rejuvenate the old cars. Last week I was in a hybrid consist (3622+3812, I think), the ASA was working but - get that - the Type 7's PA system wasn't! That was annoying. The sign said everything it needed to say, but in order to hear the announcements you had to be directly under a speaker, standing on your tip-toes, without anyone talking around you. Saying it was hardly audible would be a major understatement. It was actually easier to hear the announcements from the trailing type 8 when the doors were open at stations
Also, last week I've spotted a hybrid consist on the C line. It was the first type 8 I've seen on the C line since they were shifted back to the B.