Getting same T T puzzle twice

Hello, sorry to bother you, but I am subscribing to Tactics Trainer - 25 puzzles a day and I got puzzle No. 42958 twice.  First on May 29th and again on June 4th.  Is this a bug?  Don't we suppose to get only puzzles we didn't got yet?  If we don't suppo0se to get repeats and if this is not the right place to report this, where should I be reporting this? 

Thank you very much for reply.

PomonaU

It may just be random chance. 

I often get a puzzle twice in a row if I fail it the first time.

That's what I call "pity" mode on the TT and happens when the TT decides you need to review a puzzle.  Far more annoying is "dumb sh#t" mode as Mwotsch described where the TT decides you've missed a problem enough times that it needs special attention.  The problem with these modes is that your rating becomes inflated and you may have to reset the TT to erase your history and start over again.  

Not really, it will naturally go back down if repeats have made it too high and the problems at your rating are too hard for you.

There are far worse problems with the rating system: the massive emphasis on speed and credit for partial solutions.

Maybe it only happens if you do a massive amount of TT training, but my experience is all I can go on Scottrf.  I was in the mid 1700's with a high score of 1850 when I reset because I was getting so many repeats.  My current 1500 rating is much more accurate.  What would happen is my rating would slide down and then after about 30 puzzles the TT would shift to "pity" mode and start feeding me "review" puzzles.  As untalented as I am, even I can usually nail a problem that I've seen an hour or so before!   Of course I had a 23,000 problem history then and staff has indicated in another thread that over 20k problems TT may have trouble not repeating puzzles.  Like most on this site, I have a love/hate relationship with the TT.

There are only a limited number of patterns, once you've done 23,000 you probably just know a lot of the patterns to an extent. I vary rarely see concepts I don't know now, even if I haven't seen the exact problem, it's just working out the features of the position, which patterns are relevant, move orders, defensive resources etc.

But I do get the problem when you sometimes get too many repeats, just think that if that inflates your rating it will just fall when you start getting them wrong.

So, I guess that 20,000 problems is the goal. Then you've seen enough.