[1] https://github.com/zcoinofficial/zcoin/commit/b20c177032de3c...
[2] https://github.com/zcoinofficial/zcoin/commit/33796c839f7d4d...
But that change appears to do exactly what the variable name suggests setting it to zero would to : stop zcoin tx's from being included in a block.
That strongly suggests someone attempted to fix the issue by simply disabled all private transactions.
But this certainly is a bug. And it would allow you to steal funds.