Dice returns 1

WTF guys! Why does 1 come so many times? 3 out 5 rolls return 1? Why not 3 or 5 or 7?  That was not happening before. Did the algorithm change?  

The chance of any number coming up is always the same for every die roll. For every roll on a 1d6, the chance of any number coming up is always 1 in 6. Sometimes you just have a string of unfortunate rolls. Last night, my players ran into a nest of 9 specters; when the NPCs were attacking I could not roll above a "9" on a d20 for the entire encounter. The PCs, on the other hand, never missed. <shrug> C'est la guerre.

yeah...  my group, 6 players, rolled 1's on attacks for 2/3 of a combat encounter last week.  week before rolling 1's on attacks / skills, one player rolled 7 1's in a row with others getting some 1's as well. *working as intended*

Checking to see if the dice averages are off is trivial, just roll a decently large number of dice and divide the result by the same number. Spoilers, the average is fine. (averages of sets of 100 d10 rolls)