php7.3 failure on enable spx

[tsukasa-mixer]

PHP         : /usr/bin/php7.3 
PHP_SAPI    : cli
PHP_VERSION : 7.3.9-1+ubuntu16.04.1+deb.sury.org+1
ZEND_VERSION: 3.3.9

> phpize7.3
Configuring for:
PHP Api Version:         20180731
Zend Module Api No:      20180731
Zend Extension Api No:   320180731

terminated by signal SIGSEGV (Address boundary error)

spx_gc_traced_7_3.log

[NoiseByNorthwest]

Do you have a Dockerfile ? I've tried to reproduce it on various 7.3.9 images without success.