I have three of those exact GS405B Hucules stands and don't have that issue, but the foam on my stands does in fact react with the nitrocellulose finish on my guitars, so I need to cover the foam with old cotton socks to prevent that.
Other issues I have come up against with this stand are a loose vertical shaft to base connection, non-adjustable supports to allow the guitar to rest squarely on the bottom supports; some of my guitars rest on the outer edge of the binding (ouch!), etc. On one of my stands, one of the formed plastic shims at the base of the vertical shaft cracked and fell out. So I inquired if I could purchase a new set. Hercules said NO! All in all, I don't recommend this guitar stand to my friends.
On the bright side, my friend has a garage that has a welder, a 13# sledge hammer, a refrigerator full of beer, a couple of big-screen TVs, etc. and he is fully confident that he can modify these stands to my complete satisfaction.
He has already cut off the wrap-around at the neck rest as it just got in the way for me. It defeats the safety purpose of the wrap-around, but like I said it just got in the way. You can see the modified neck rest in the attached photo (from an old LTG thread); it now looks like any other neck rest. Because this was a quick photo session, I do not have the cotton socks placed over the foam.
Tommy