I am not sure when this started occurring, but recently a few of my users complained that they are unable to change their passwords. They click on the "Lost Password" link. They receive the email with the link to reset the password.
Upon clicking on the link, they are redirected to "https://…./my-account/lost-password/?show-reset-form=true". However, the Reset Password form does not show up. Instead, they receive the original Lost Password screen prompting them to enter username/email so the Lost Password email can be sent to them.
So the users are in this circular loop. They are unable to change the password.
Looking at the relevant code (https://github.com/woocommerce/woocommerce/blob/a3ec0bf85aa6a55ed3241fc2a30a397e4b1273dc/includes/shortcodes/class-wc-shortcode-my-account.php#L215), it seems that the "wp-resetpass-" cookie is not being set.
Ask your hosting provider if somehow they are caching the "my-account" and "lost-password" pages. If they are, that can explain this behaviour. Atleast, that was the case with me. Once those URL's were excluded from cache, the Reset Password" form showed up successfully.
Have you experienced this issue before? What did you find?