Hi guys!
The same problem. The same symptoms as @ale91. The problem is in the compatibility of Woocommerce 3.12 and Polylang 2.2.
I confirm that if Woocommerce 3.12 and Polylang 2.2 work together, the pages load very long. Defined that the problem disappears if:
1. Disable only Woocommerce.
2. Disable only Polylang.
In order to confirm the problem of compatibility versions did the following:
Removed Polylang 2.2, installed Polylang 2.1.1 the problem solved and the site again works quickly. (In this case, by “solved” I mean a temporary solution to the problem).