from a players view point: maybe your team's concentration and/or determination is low overall or stamina
tactically try playing as safe as you can during that time, lower the tempo, increase time wasting, play deeper D, maybe even contain mentality
Sometimes if you dominate a game and you are the better team (more possession/chances) then decreasing the Tempo and increasing Time-Wasting at the end of the game can lead to this problem and you will concede late goals. Be careful! If you are the better team for 85 minutes then this is because you have chosen a very good tactic and the right tempo for this game. If you increase time-wasting then you suddenly change this winning tactic and your team will play less offensive. The opposing team can use this and turn the game around. I suggest you only start time-wasting at the very end, maybe 85th minute and not before... Good luck!