Volume glitch in hydrophone operator's reporting

[Greystone]

Bizarre: when my hydrophone operator makes reports on contacts he gets, he'll report "Warship (or Merchant) 230 degrees..." etc.
All fine and good but oddly, on the second number (3 in the above example), he articulates the number at a VERY high volume, and then continues on with his report sequence at the normal volume. Only the second number in the number sequence, if it's a 2 or a 3, does the increased volume occur. Once the second number in the report (the 3 in 230) becomes a 4 (Warship at 240 degrees) does the volume increase at the 2nd number stop. It appears to only happen when the 2nd number is either a 2 or a 3; this hasn't happened when the 2nd number is a 4 or a 5. The volume increase is pretty substantial and a bit unnerving when not expected.
Have any of you had this problem? I'm running SH3 with GWX3 and no sound mods are installed. Thanks.