No. Not at all. Anyone could fix it in two minutes with a stick or a 2X4 and two feet of tape.

As for what's behind cabinets? That's nothing.

personally, I'd replace that section, and mastic seal
all joints. easy enough to do in retrofit.

I'd also question the hole in the ceiling with electrical
exiting.

holes open to attic or walls behind cabinets & boxing
are forever air leakage sites, plus openings for rodents.

seal now while it is all open.

best of luck

It's got a couple dents in it, but I'm not seeing substantially impeded air flow here. I wouldn't worry about it.

On how many forums did you post this?

Do you plan to return and let us all know what the responses were?

Sheesh!!!!!

Hi @saltidawg, I posted first on the Air conditioning/heating forum as it was a ducting issue and then in the home repair forum - that's it. I'm finding both helpful and I appreciate everyone's advice. I have a lot going on with all this but had every intention to come back and post more news as I have any and of course to thank all who posted. Thank you for your interest with this! To date this is the situation...

Kitchen got installed yesterday and is complete. The ducting is all closed in right now. This renovation has been an ongoing nightmare and so when I saw the ducting crushed and dented I had had it up to here. He said he fixed it up better before he closed it and that there will be no problem with it. As I missed what he did to it before closing it up I asked he provide access so I don't have to destroy cabinets in the case I need to redo it. Apparently I can unscrew the panels covering it up inside the cabinets but not the panel that is over the range. I showed the photos to the person who did the ducting and he didn't believe he would have been able to undo what he did. But he also said as some have posted that there most likely won't be a problem but we'll only know when we install the actual hood range and see at that point and if there was a need to redo it they should be held responsible. I haven't decided how I was going to handle it yet. This is the third issue with these kitchen cabinet people. I have posted pics of how the cabinets arrived in a previous forum. So, between the cabinets and now the installer damaging my ducting....I need to think of my next steps as they have been paid in full by certified cheque at delivery time.

I'm feeling reassured after a few comments saying it should be fine. What's worrying me more now is the electrical having been done like that. I was obviously a shortcut for them to do that but I didn't think of air leaks and rodents. Above the ceiling is a flat roof - probably about only a foot of crawl space that is insulated. Behind the kitchen wall where the hood fan will go is cinder block separating my dwelling from the neighbor. The opposite wall is an interior wall between another dwelling. I'm sandwiched in between 2 dwellings. The kitchen cabs go to the ceiling being closed at the top with a small moulding. The holes from that electrical work have not been closed up. Should I really be worried? Do I go back to that electrical company and say something? I haven't gotten that electrical bill yet but I know it will be a biggie! Thanks for listening...

This is not air conditioning duct - don't understand why the A/C double post... but moving on.

I also think that it would be fine with a minimal effort but the cabinet installers. As others have suggested, use a flashlight and a mirror to inspect (showing my age) or hire a plumber with a borescope )rich man's suggestion) or tape a cell phone to a stick and video it or....