Customer welds several sheets, which are located in one Weld-part. To publish Weld Features to Teamcenter, they should be located in the separate component - Weld-container.
Customer uses Weld-container for Weld Features, but Weld Features are not published to TC.
Solution
haveStructure of Weld Assembly, which customer uses: Weld-container is child of Weld-part.

NXManager actually doesn't publish Weld Features to TC, if Weld-container is a child of Weld-part.
Recommended Weld Assembly structure is described here: "Publishing weld and datum points to Teamcenter"

i.e. Weld-container should have the same level as Weld-part in the BOM structure. In this case publishing Weld features to TC is successeful.
The following restriction information is added to the NX 1926 Doc.
"Weld container cannot be child of the component parts being joined in an assembly: NX does not publish such weld features in TC. We recommend you to create the weld container at the same level as the component parts being joined."
Notes and References
PR_8441559
Hardware/Software Configuration
Platform: INTEL
OS: windows
OS Version: 1064
Product: NX
Application: KDA
Version: V1899
Function: WELD_ASSISTANT
Ref: 002-8017638