Maxscale memory leak (2.4.15)

Hi,
Our MaxScale server runs about 200M memory generally, but sometimes it surge to about 20G within 5 minutes, and memory never goes down even after workload peak.

We checked the time of the problem, and we found that a select query was reading a large result set (tens of millions of rows). But when we execute the select query alone, problem cannot be reproduced.