MySQL using more memory than it can?

MySQL Version 5.6.24-72.2-log x86_64 …
MEMORY USAGE Max Memory Ever Allocated : 70.35 G
Configured Max Per-thread Buffers : 972 M
Configured Max Global Buffers : 70.04 G
Configured Max Memory Limit : 70.99 G
Physical Memory : 125.88 G
Max memory limit seem to be within acceptable norms …

If according to the tuner MySQL can never use more than 70.99 G. What else can I check for on what the MySQL process is doing to use more than double the memory?

This is running Percona server 5.6.

I can post the entire tuner output if requested.