Can water going in the waste port cause damage?

Short version of below: Can water going in the waste port by mostake cause damage? Happened for abiut 5 minutes?

Hey all, after a year of using a portable Unger water system I splashed out on a facelift osmo compact 525litre system. Over covid I couldn't travel from Ireland to UK to have it fitted. I found a guy to fit it here locally to me and it's all bolted in and wired up now but the guy that fit it, and this sounds so stupid now, but on the under ports he told me which was the intake port and which was the waste(so I thought)

So for the first fill today, I was instructed to open the yellow valve on the membrane to do a 15 minute flush and then close it and the tank will fill up with water. So I connected it up and noticed very little water coming out the waste(altho it should have been 100% of the water while the port was opened) and most was going into the tank. So I wondered did the guy who fit the under ports have the waste and intake mixed up so I swapped the intake water to what I thought was the waste port(but was obviously the intake) and Perfect, all the water was coming out the waste now(which is where I had the water going in)

What I am wondering is can I have done damage to the system from the water going in the waste instead of the intake by mistake?

Also is the only way to empty the tank just to have it come out of the hose reel?

Thanks all

I did it once briefly and it didn't, the only way to find out is to try it.

Did you measure the ppm because if I understand you were feeding the membrane through the waste pipe which will cause damage if run for a long time.