Did you receive a high number of requests lately that could have increases the load of the instance?
Can you monitor the status of the instance when performing those tasks you were mentioning?
ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS
ps -e -o pcpu,nice,state,cputime,args --sort -pcpu | head -10
Please share the output of those commands if you need help.