Cellular data becomes virtually unusable AFTER a call ends on iPhone Air (DSDS setup)

Hi everyone,

I am currently using a dual SIM (DSDS) setup on my iPhone Air with two different carriers. My primary line (IMEI1) is on 5G, and my secondary line (IMEI2) is on LTE.

I have the "Allow Cellular Data Switching" option toggled ON. Because of this feature, my cellular data works perfectly fine during an active phone call, as it temporarily routes the data through the voice line.

However, I am experiencing a recurring and frustrating issue. Immediately after making or receiving a call (even if the line just rings and no one picks up), my cellular data speed drops drastically to the point where it becomes entirely unusable. The signal bars still indicate a strong, normal network connection, but the actual data throughput is practically zero.

This doesn't happen every single time, but I'd estimate it occurs about 50% of the time. Temporarily toggling Airplane Mode on and off resets the connection and resolves the slow data issue.

I am wondering if this is a known iOS modem firmware issue on the iPhone Air, a baseband routing bug during the network re-attachment process, or a carrier-specific issue.

Has anyone else experienced this specific symptom with their dual SIM setup on the new iPhone Air or other recent models? Is there any known fix or workaround other than the Airplane Mode toggle?

Thanks in advance.