So, I can give the all-clear. I had contact with LeTech and it is probably residue from production.
I have now cleaned everything and reassembled it.
My guess is that the parts were not cleaned properly after production and this caused the liquid to build up at the bottom over time...
Interesting point. The complete dismantling of the original ladder and the assembly of the LeTech ladder took me a total of around 45 minutes. However, 1.5 hours were shown on the invoice when the ladder was mounted by LeTech back in novembre.
Lubrication from the mandrel?
By the hour billing time is not just the moments the worker spends doing the actual work. Its receiving the ticket, retrieving the product, handling the truck, clean up etc. "Staging" is a common term. I don't know really all the details here, I'm just pointing this out because there seems to continuous confusion when someone that doesn't do or or manage piecemeal work, does it for themselves, and discounts all the non productive time as inconsequential to the billing process.
I'll give you an anecdotal example. We do Industrial electrical and controls work, but menial tasks pay just as much as complicated ones, so, if a customer calls and says, "I need 4 lights in an office swapped to LED, will you handle it". Sure, we'll do it. Converting that one office includes material procurement, travel and clean up and billing. So, you're looking at a realistic 4 hours of total time, and that's what I'll be billing. Now, say its 5 offices, for 20 lights. Well, the staging will only be slightly longer, so, it would be about a days worth of work so now you're looking at 8 hours. You're getting 5x the production for 2 x the cost.
Where you DO get banged by automotive shops, at least here in the US, is they calculate a time for each job done individually, put it in a book, and they may to bill you book time for each procedure if you're not observant. Time and material doesn't mean what you think it means. It isn't like hiring a painter. Also, women and minorities tend to have less exposure to process management of trades, and low and behold, guess who pays significantly more when analyzed. So yea, if you're typecast as sucker, there are unscrupulous people that will take advantage of that. Never be afraid to ask questions and stand up for yourself. Honest people are never offended by inquiries about their work. Ever. ... There's your Friday morning shot of wisdom.