LTC6994-2 signal inverted and time delayed
That is the correct functionality, per page 14 of the datasheet:


  If the input doesn’t remain high or low long enough for
  OUT to follow, the timing will restart on the next transition.
  Also unlike the LTC6994-1, the output pulse width can
  never be less than tDELAY. Therefore, the LTC6994-2 can
  generate pulses with a defined minimum width.


Because the delay timer is reset on each edge transition, the LTC6994-2 is also operating as a pulse discriminator. For a valid pulse to be transmitted, the minimum pulse width must be at least 1 tdelay.