Weird to read all the comments with regard to SDTM after not making it up a ramp.. As far as I'm concerned this is a staple of good pinball design, assuming the flipper power is in good order, and the ball is not getting caught up etc.
This is even articulated somewhat in many classics examples.. to mind atm, EATPM (.. "oh yeah.. OH noooo").. or Demolition man.. "Oh Sh!t, no!".. lol. 100% the SDTM risk is intentional, and not a poor design.
Most comments might also be just adjustment issues. I've played TWD where the magnet drops it SDTM.. it sucks for sure.. but I know it's an adjustment, as I've played them where it does not behave this way. Exact same scenario with MET / Sparky.