iPhone 11, text forwarding reply issues

Hello, I recently purchased the iPhone 11 as an additional line. Currently I have an 8 plus (primary line), 8 (work line), 6s plus (unused extra line) and a Macbook Air.

Prior to the 11, I forwarded all my texts from my 8 plus to the additional devices (8, 6s plus and the Macbook) and would have no issues receiving/sending texts from the 8 plus.

With the addition of the 11 and all the text forwarding settings matching the other devices. I can only receive the forwarded texts from the 8 plus and I cannot reply. When I try to repIy, I get hit with "Number not available. Which number would you like to send the message with?". At this point, I'm given the option to use the iPhone 11 phone number and I cannot reply with the forwarded 8 plus number.

I've checked the settings a million times. Text forwarding it toggled on the 8 plus the 11. The 11 is set to receive messages from the 8 plus and to start new conversations with the 8 plus phone number. iCloud accounts are the same across the board. iCloud, iMessage was logged in and out of both phones numerous times as well.

I have a feeling that the dual sim capability is causing the issue. Anyone else experience this?