A couple of things our club has found over the years, now standard practice for all club members to do to their Loks.
1. set CV11 = 0. This is the timeout timer, depending on your system, how many addresses are in the refresh list, etc. Just set to 0.
2. turn off DC. Bit flag in CV29, lets your Lok run on DC layout power. Some systems will trick your Lok into thinking power is DC, then revert to DCC, then dc. Random pauses. Only enable this before going to a DC layout, Otherwise, turn off.
This eliminates most decoder issues.
Check that your solder joints are not cold joints. Always use flux when soldering, even if the solder says it has flux. (NOT ACID FLUX!!!)