The diameter of the conduit was too small.
The conduit must be two sizes larger than the piping itself, such that a 25 mm pex pipe should be in a 40 mm conduit and a 20 mm pex pipe should be in a 32 mm conduit.
The piping in the picture is 25 mm piping in 32 mm conduit.
Why is this important?
Pex piping is installed in conduit to allow for easy future maintenance. If a pipe or connection springs a leak the floor and walls don't need to be opened for the pipe replacement. If the conduit is sized properly and proper radius is maintained during installation the piping can be easy removed and a new one pulled in place. If the conduit is too small it will be impossible to pull in a new pipe.
How did this happen? The manufactures sell either sleeved or non-sleeved piping. Sometimes companies purchase non-sleeved piping, put the piping in their own sleeve, and then sell these rolls to stores. It is in this latter scenario that disastrous mistakes like this occur.