Variation in the 3D printing process of each piece can create either a Frame that makes it necessary to sand it down a bit or remove the Tab entirely, which is mentioned in the product description, but then works with friction alone OR creates one that has less friction but a working Tab creating an audible cue like shown in the Video - Yours appears to be the former.
Having purchased two Frames myself I can report BOTH possibilities to happen from a 3D File that has not had changes in dimensions between those two prints.
Why this happens I cannot say - Might be a change in orientation for the layering of the 3D Print, might be a different setting for the 3D Printer, might be even a different 3D Printer - None of this can be controlled by the Creators.
Anyway... A solution to both possible outcomes can already be found in the Product Description.
It's a "pity" you can't handle or afford some sanding as you should then simply not fly the Multicopter this was made for.