The ATF has recently made a decision to review Trusts for legal sufficiency. While this may slow things down for those using generic trust for NFA purchases (Quicken, Legal Zoom, Gun Store Trusts) I think its a good idea and will protect many from unknowingly violating the NFA.
We have seen several issues where the ATF is declaring trusts to be invalid that are in fact valid under various state laws. They claim they are not practicing law in those states and will not give legal advise. They suggest that you have the trust reviewed by a lawyer to tell you why it is invalid or make changes to the trust to make it valid.
If your trust was rejected by ATF we can help by reviewing and or amending the trust with our network of 75 attorneys in more than 40 states.