Of course, it's a bug. Standard two-way radios operate on a direct communication system.

We encountered a similar issue on a completely vanilla server on the Kolguev map. After deploying, tuning to a specific frequency yields no results; we cannot hear each other over the radios—only via standard proximity voice chat. This problem has persisted since version 1.8 and severely hinders squad communication at specific locations, forcing us to rely on text chat. The issue arises when there is no base nearby.

Additionally, when a large tower is present on the Kolguev map, attempting to speak on the US frequency (48) results in us not being heard—yet no notification icon appears to indicate this failure. However, we can still hear the conversations of people within the radio transmission range of the bases. This creates situations where we need to quickly cut off the enemy's communications, but the commander misses the request in the chat to dig up the base, and we end up getting driven out of that position.