The short answer is yes CPU spike can occur if there's a high number of errors in a short interval. But it strongly depends on the type of the errors, the amount of number and their content.  Errors always impact the hit rates as it can decrease or increase it.

For example if you have network errors due to timeout the LG will wait till that timeout and as a consequence the hit rate will decrease.

CPU spike can also be an issue if it lasts a long time. Having spike for few seconds should not be an issue but during hours for sure it will decrease the hit rate.