Unrecognized signature of debug types & Symbol '$$000000' is multiply defined

[jj2007]

For some days now, I've been fighting with an odd little problem:

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POLINK: warning: Unrecognized signature of debug types in object 'Tmp_File.obj'; ignored.
POLINK: warning: Unrecognized signature of debug symbols in object 'Tmp_File.obj'; ignored.
Unique object file Tmp_File.obj is assembled with MASM and /Zi /Zd /Zf
Linker commandline has /debug

Besides, sometimes polink chokes with:
Symbol '$$000000' is multiply defined: 'tmp_file.obj' and 'tmp_file.obj'

There is no such symbol in the *.lst file, and Tmp_File.obj is the only object file on the commandline.

This happens with the new polink and the version of March 15. With both of them, I can't see symbols in Olly, while polink of April 2011 shows them to me.

Any idea what could cause this trouble?

P.S.: The combi of ...
Masm 6.15 with /Zi /Zd
Polink March 2015 with /debug

... works just fine. No warnings, and symbols show up in Olly.

P.S.: I got a partial answer here:

Added support for Pelles C Debug Info, dropped support for Microsoft CodeView info.