Ditto clancy_boy's comments.
As a quick test, and if you have enough of the original hose to spare, you could snip off an inch or so and remake the connection, the indents as discussed above, will be gone. Also, you can get, for want of a better term, double wrapped hose clamps, and these allow a much tighter fit than a single which can begin to thread strip before getting tight enough.
It might also (unlikely, but possible) be that you need to back off the pressure shut off adjusting screw so that the pump shuts down sooner, and under less pressure.
A wise man once told me he wanted to stay fit enough to run a marathon on his hundredth birthday. Another said he wanted to be shot by a jealous husband on his, I'm with the latter. God bless you Richard.
Carpet Cleaning is what I do, it's not who I am.