Activation issue (for users with empty/space characters in its username)

Hi Profile Builder team,

We have found an issue with user activation process.

Steps to reproduce:

1. Register a new user with space/empty character in its name (for example, Test User);
2. Open activation email and press an activation link.

Expected result: user is activated, and can see a default message – Your email was successfully confirmed! User is redirected back to login form.

Actual result: user can see only a white screen. User is not activated. No login form is available. User should press the activation link one more time to get the account activated and get Your email was successfully confirmed! message.

Additional info: Profile Builder logs contains a lot of similar activation errors (activation key is duplicated a lot of times). Please see details below.

[2017-12-21 17:04:33] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:04:34] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:04:34] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:04:35] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:04:35] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:04:35] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:04:36] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:04:36] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:05:35] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:05:36] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:05:44] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []
[2017-12-21 17:05:45] wvsso.ERROR: Profile Builder activation error: This username is already activated! Activation key: 3f4be565d08ef2a3. See wp_signups table for details. [] []

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