ABAP Systems stopped updating SLD

Question

Last week I added my dev PI SLD system as a data supplier to my existing Solution Manager based SLD.  Up to then my ABAP and Java systems were regularly updating their entries in the Solman SLD.  After adding  the dev PI SLD, I see updates about the PI landscape's ABAP systems in Solman (previously not defined) and I get regular updates from all my Java systems but the updates from ALL my non-PI ABAP systems have stopped. 
I have checked in RZ70 and done test runs etc but nothing seems to make the data actually appear in my Solman SLD.  My Java stacks, including my production and dev Solman systems appear in the dev PI SLD as Java systems.  The Solman systems are dual stack and appear under both ABAP and Java systems in the Solman SLD but only the Java stack appears in the PI SLD.
Any ideas what I can have done to stop the updates reaching Solman's SLD?
Why only ABAP?
Why does Solman SLD get updates from PI SLD about its ABAP stacks?

Answer 1

<h1>I have:</h1>
<h2>* checked all RFC destinations</h2>
<h2>* run RZ70 in the ABAP system to push the data manually without error messages in the job log, SLD log or SM21 system log</h2>
<h2>* restarted the Solution Manager system containing the SLD and rerun RZ70</h2>
None of these basic checks have corrected the situation. 
In desperation I deleted the connection from my Solman SLD to the PI SLD overnight.  The PI SLD system has still managed to do an update into the Solman SLD this morning for it's own ABAP stack.  It didn't update the QA PI data and none of the other 29 ABAP systems have updated either. 
NOTE that this problem doesn't just affect one ABAP system.  I have 29 ABAP systems defined in my Solman SLD (some are deactivated but most are live) and none of the live ones are updating.  This has got to mean that there is something wrong in the Solman SLD, not the ABAP systems, but the only thing that has changed, to my knowledge, was the addition of the PI dev systems SLD as a data supplier.
<h1>A question.</h1>
If I want my Solman SLD to be the repository of administrative data but I want my PI dev SLD to know about all systems, in which system should I be adding a data supplier pointing to the other?