Would it cause an issue if 16-18-18-36 was mixed with 16-20-20-38? Both kits being Corsair Vengeance Pro RGB? the 16-18-18-36 is V. 4.32 and 16-20-20-38 is V3.32. Both are 3200Mhz though.
More than likely it will cause an issue however Intel CPU's are more tolerant whereas Ryzen are more picky.
The CL indicates there is a variation in clock cycle Timings for tRAS so they are binned differently. Sometimes they will work but issues commonly arise. These issues generally occur as sudden shutdowns or unexpected reboots.
Essentially, It is how many clock cycles it takes for the RAM module to access a specific set of data in one of its columns (tRAS) and make that data available to its output pins, starting from when a memory controller tells it to.
Memory chips require time to fully execute commands. (done in nanoseconds) Executing commands too quickly can result in data corruption and system instability.
No harm would result in trying. Your system may refuse to boot or set frequency well below their rated frequency but that's all.