Cannot initiate connection with a device when there is another device like it nearby

We are developing a BLE device based on a STM32WB5MM. The device acts as a server and has configured the connection with bonding (and a passkey).

We have a problem connecting to the device when several devices of the same type coexist in the same place (about 3/4 devices in an area of 5 meters radius). It is difficult to start the connection, in the order of minutes (sometimes it is not even possible to start the connection). However, once the connection is established (because we move away from the area) it remains stable (even if we return to the area with more devices).

Any idea why this might be? All devices have the same name. This is the only thing that comes to mind. Can this cause a problem at the time of authentication (bonding)? We have noticed that if a mobile device (which is our client) has a paired device, it cannot connect/pair to another one until the information of the previous device has been deleted on the mobile. If so, just modifying the name of the advertising is enough or is it necessary to modify something else?

Best regards and thanks in advance.