PHP7 stability?

Question

PHP

Same site, same settings, same server, same load.
PHP7:

PHP5:

Debian system. Load forum SMF, DB load CPU < 10% on a separate server.
Should I write in a PHP bug tracker? At low RPS, everything works stably, and even version 7 is 25% faster than PHP5 (page generation time) and consumes half the memory until it goes into a regression.