Administrator: Customer + Carts Out of Memory

-- HikaShop version -- : 2.6.1
-- Joomla version -- : 3.4.8
-- PHP version -- : 5.6.
-- Browser(s) name and version -- : FF 44.02, Chrome, Safari
-- Error-message(debug-mod must be tuned on) -- : Most of the time its something like:

Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 72 bytes) in /home/actnow/public_html/administrator/components/com_hikashop/classes/currency.php on line 1295

As we play with the memory limit in PHP, we can sometimes go as far as getting this message:

Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 65552 bytes) in /home/actnow/public_html/libraries/joomla/filter/input.php on line 980

When trying to list customer carts on the back end we get Allowed memory size of X exhausted...normally on /administrator/components/com_hikashop/classes/currency.php on line 1295, but the exact file and location can vary.

We have increased the php memory_limit from 128M to 512M to no avail. This is the only function that we have this happen, and I can't figure out when it started.

I changed the cart retention settings to reduce the size of the table, and I only see 43 records in the _hikashop_cart table.

I'm assuming something is corrupt in the data and don't know how to fix it. So I purged the data in both the _hikashop_cart and _hikashop_cart_product tables.

Is there any other location I need to clean things up with and is this the right thing to do? Once I purged the contents of those two tables, the function works properly with only 128M in PHP memory_limit as it had before.

Thanks,

Kevin