Last week on March 7, Prowler again briefly flared while I was imaging it with the same telescope, Note the brightening of the trail near the left end of it:
It is a flare of the same short specular type as that of last year. It was captured in one of three brief 30-second exposure images taken near 03:45UT: the flare is close to the end of the trail in the second image, i.e. occuring at about 03:45:10 UT (March 7, 2015). Here is a stack of all three images:
These brief specular flares are superimposed on what seems to be another, very slow periodicity in brightness.
Prowler itself is a very interesting, enigmatic object. It was a clandestine launch from Space Shuttle STS-38 in 1990 and long existed in the realm of rumours only. It was a top secret experimental satellite with stealth characteristics, meant to make close inspections of third party satellites in GEO orbit. I have written an extensive in-depth post on the story of Prowler before which you can read here.