Haven't had such a problem in the 3 LXs that we've owned. If you've still got the Conti Self-seals that might be the problem as was suggested.
On another subject... WELCOME to 3CF from our West Virginia LXs in the Mid-Ohio River Valley. Since you have a Heritage Edition (as do I), please post your build info in my
Make Our Own Build Sequence for Heritage Editions thread. What's requested is defined in Post#1 and you can see who else here has registered as an H.E. owner.