FWIW, Wahoo responded quickly and here's their advice, for those who have this issue:
Thank you for reaching out and I am sorry that you are experiencing this issue with your ELEMNT computer. We are aware that a number of users are experiencing connectivity issues on iOS after the iOS 13.5.1 update and our development team is actively working on improvements to connection stability. In the interim, please ensure you are on the latest version of iOS (13.6) and the ELEMNT app via the Apple App Store, then follow the steps below to reset the ELEMNT's connection with the phone. Even if you have previously re-paired your device, please complete these steps exactly in order once again as the ordering is critical to resolving the connection stability
Step 1: Forgetting the ELEMNT Companion in the companion app- Open the companion app
- Select settings
- Scroll to the bottom and select Unpair ELEMNT
Step 2: Forgetting the phone on the ELEMNT Bolt- Power on the ELEMNT Bolt
- Press the power button to bring up the menu
- Select forget phone
Step 3: Forgetting the ELEMNT in your phone's Bluetooth settings- Open the iOS settings app
- Select Bluetooth
- Under my devices, find the ELEMNT and select the info button on the right
- Select forget this device
- Repeat these steps for any duplicate listings of the device
- Important: Toggle the Bluetooth switch at the top of the screen off for 10 seconds, then back on
Step 4: Re-pairing the ELEMNT to your phone- Quickly press the left-side button on your ELEMNT to display the menu
- Scroll (with the right-side buttons) to either "PAIR PHONE" or "FORGET PHONE"
- Your device may reboot, displaying the QR code when it powers back on
- If the QR code does not immediately display on reboot, return to the settings menu on the ELEMNT and select "PAIR PHONE" - the QR code should now be shown
- Return to the ELEMNT Companion App on your device, then navigate to the settings menu to add the ELEMNT
- Make sure that once the QR code is scanned that you allow any requested permissions from the pop up dialog
- Once this is complete, go to Bluetooth settings once again, select the circled 'i' next to your ELEMNT in the list, and ensure that 'Allow system notifications' is enabled
Should you experience connectivity problems after completing the reset procedure above the entire process generally does not need to be repeated, please attempt the steps below to restore the connection before repeating the process above.- Toggle Bluetooth off in iOS settings for 10 seconds, then back on
- If this does not allow your ELEMNT to connect to the app, restart your phone and ELEMNT