Woocommerce NOT recording order – weird order number

I understand that woocommerce assigns order numbers based on post ID and there can be gaps in order numbers. However, my woocommerce store is experiencing something weird over the last 5 months and it is now a big problem. My order numbers as of writing this post are up to 56XXX. However, once a month for the past 5 months, woocommerce will drop an order due to it being assigned an OLD order number in the range 54XXX. Sometimes the orders are duplicate of orders that were previously successfully completed and shipped, and sometimes they are just not in the database AT ALL. The twist here is that the emails go out to us and the customer that an order has been received, however there is no record of this as a new order in woocommerce. they are also being charged on their cards through our merchant.

So here is the range and dates of the orders that we know about that were never shipped because they were not entered into the system:

order number
54815
march 26

54816
april 07

54817 – doesnt even show up in woocommerce at all
may 27

54818
july 07
54818 jan 26 – there is an order that was successfully generated and completed in january with this same order number.

54819
july 14

so what im seeing is that for some unexplainable reason – woocommerce is processing and order and rather than starting at the 56XXX range it will assign 5481X sequentially and they just will not show up as an actual order in the backend. so i anticipate that the next time this happens next month that the number will be 54820 and will fail to show as a new order and the customer will never get their product. its all so random, but obviously has a pattern. we have never installed anything in regard to customizing order numbers as we figured woocommerce can do its own thing.

here is the full process as described by my client at the point in which they have a customer service issue on their hands.

customer calls in and says they got nothing shipped to them ever. then rks (my client) goes to email confirmations and finds the order (in outlook), but the order DOES NOT exist in woocommerce OR its a previously completed order with the same order number but no record of a new order with that number (usually an order from MONTHS prior – typically in january).

RKS is getting an order has been received email. customer is getting an order has been processed email (with the erroneous order number) however, the order doesnt exist in woocommerce. therefore never sent to shipping integration system where all woocommerce orders are sent out.

shiprush – shipper they are using. polls woo every 5 minutes and looks for something new. every time it has something new – it puts it in their platform where they can create labels and ship the product. personally i dont think this has anything to do with the problem

if woocommerce doesnt send the info to shiprush then they have no idea to fulfill the order. hence customer never gets item.

problem is – woocommerce never records the new order – so its never pushed out.

I personally exported the database and combed through it to see if there were multiple instances of post ID’s being assigned as i figured a larger site could be trying to assign duplicate post IDs to assets and orders alike. nothing. no duplicates whatsoever.

looking for any guidance or feedback on this. 18 years in the biz and this is one of the weirdest things ive encountered.