This just happened to me too !  We each had 5 checkers and I had an advantage and a plan and my opponent claimed a draw. He knew he would lose and Fly or Die gave him a way out. We hadn't even moved with 5 on 5 yet.
Please go back to the 40 move and it's a draw.  This is not fair.
An opponent cannot simply declare a draw just because they want to.  This is not a good rule.
Draws are supposed to be mutually agreed on.
In the American Checker Federation (ACF), a tie game is declared a draw. A draw can be declared either by mutual agreement between players, through the strict 40-move rule, or if the same board position is repeated three times with the same player to move.

i just had a game with 5 checkers each player.  I had 26 seconds and other player had 11 seconds. He was able to claim draw!  I HATE THESE RULES AND PLAYING HERE ANY MORE

If you repeat the same move three times, the game will automatically end in a draw. Just keep track of your moves and try not to repeat the same move three times. Even if your opponent repeats the same moves, as long as you change your moves, the game will not automatically end in a draw.

There is one error, though. I'm not sure if they've fixed it yet, but the game will automatically declare a draw when each player has only one piece left. So even if you have a winning position, if both players end up with just one piece, the game will still be declared a draw.