Some people write the traditional "CMs+T4s" in the fractal LFG but after doing 2 fractals they reveal (or don't) that they have already done one of the fractals and leave. Saying "I forgot to mention" is a big lie, we all know it is faster to find people if you advertise for a full run. When that happens once it makes the last 2 random guys whose team abandoned them to do exactly the same thing and the cycle repeats.
Here is the solution: if for example your healer abandoned you after doing 1 fractal PLEASE write in lfg that you have already done that specific daily fractal. If you cannot find a group for half dailies then you could advertise for all the dailies and REPEAT the done fractal again even if you already got the reward. It is an honorable thing to do. Lying is the bad option, don't do that, breaking the cycle of lying is the good option. Many pugs will be thankful to you.