You can do a search on this on this site and find a whole group of people who have experienced this issue. We have replaced 3 sets of hydraulic lines until we got the right set of lines and fittings (especially) from HWH. The last set of lines had different fittings and have held up well for a year and a half. Some will tell you it's heat from the radiator causing the problem. Ours failed on the third set of hoses (second replacement) when the coach sat in Palm Springs and we cycled the slide in an out twice a day for 7 days and never started the engine. After this, HWH sent a different set and they have not failed as of yet, 1 + years, and 12,000 miles later. We moved the hoses away from the radiator, but in our HWH tech's view, and ours, the radiator doesn't get hot enough to make a difference on these hoses.
I would recommend you find a HWH representative who has done this before to repair this issue, so they can deal with the factory, who knows a lot about this issue.
If you wish, send me a private message with your phone number and I can call you and discuss all the fixes we did that finally appear to have control of the issue, because I think we have fixed as many of these wardrobe slide hoses as anybody,and we too, had the issue with the bedroom slide stuck with the back part sticking out at an angle. When one hose leaks, the cylinders that move the slide in and out lose synchronization and need to be re-synchronized when the hoses are replaced. I can tell you how to do this as well.
Best wishes --
Former Owner, 2006 36MDDS
2010 Arctic Fox 22GK Travel Trailer
2007 Toyota Tundra