I really notice it after doing laundry or when it's windy outside.
...caulk all the seals around the pipes and sewage ejector lid
AHA, first mention about an ejector !
Are there drains to the ejector running underground ?
That could be a suspect area if there are any leaks from the
lines/tank under the slab (if there is a slab)
2nd, "After the laundry runs..."
When the washer discharges, presumably into the ejector tank,
there is a LARGE flow of water through the system.
This flow, depending of how it's routed, can SUCK traps on the line
to empty them.......then you've got an open trap to emit smells
until you use/fill that particular trap again.
The 'windy day' aspect would certainly add to any flow through
an empty trap. While I agree that the elbow on the stack, facing the wind,
could put additional pressure on the system, there would never
be enough pressure to blow the water out of a trap.
But yes, lose the elbow.
Trace everything from ejector pump to end-of-line,
and make yourself a sketch you might be able to post here.