So five games in a row you first had a mulligan with this hand.
Now someone correct me if I'm wrong here
There are 2 Gumshoos, 2 Cynthia, 1 Malasada and 20 energies in the deck, so after you had your first mulligan, each of the 4 following ones had a probability of (2*2*1*20*19*18*17)/(60*59*58*57*56*55*54)*7! = 0.12% of being the same by chance. Take that number, put it to the 4th power and inverse it and we get: A similar occurence should only happen once in 475 billion matches on average.
This is 1 million players each playing 10 matches a day everyday for 130 years...
This story strongly points to a RNG bug.
How long did the first 4 games take? That's how long the random seed presumably got stuck.
Was the starting hand after the mulligan the same too? If not, either it's not a stuck random seed or a new seed is cooked after a mulligan.
Do you also start with the same hand (no mulligan) several games in a row?
It could be that the bug(s) doesn't affect every user. This would be the case if e.g. the user ID is used in the cooking recipe but some IDs lead to bad statistical properties in the recipe.
PTCGO, please note that it's good practice to open-source the part of the code that deals with RNG.
Side note: an RNG bug could mean there's a best way to open packs!
I think that the RNG codes will never be released by pokemon because many would then just exploit them for wrong uses. Even if there was something fishy about the codes, which I rather believe there isn't, there is basically nothing you can do about it.