I am having the same issue - I recently updated my firmware to the latest Marlin (2.0). Everything was working fine; now it is not.
I have confirmed that the report, even though it is slightly different is still being generated (confirmed by running G29T in the terminal window).
I also have the Processing Timeout set to 1800 secs (30 mins, if 'secs' is truly seconds... ).
Here is what I have set up for the GCODE command:
M155 S30
@BEDLEVELVISUALIZER
G29T
M155 S3
Here is what I receive via the terminal when running a G29 or G29T command. The format seems much different. Is Bed Visualizer set up to parse this new format?
Recv: Bilinear Leveling Grid:
Recv: 0 1 2 3 4 5 6 7 8 9
Recv: 0 +0.035 -0.022 -0.075 -0.088 -0.137 -0.097 -0.125 -0.085 -0.052 -0.007
Recv: 1 +0.045 +0.005 -0.022 -0.025 -0.060 -0.003 -0.007 +0.045 +0.080 +0.132
Recv: 2 +0.155 +0.073 +0.030 +0.010 -0.025 +0.015 -0.015 +0.017 +0.040 +0.085
Recv: 3 +0.112 +0.057 +0.015 +0.015 -0.012 +0.032 +0.005 +0.055 +0.078 +0.127
Recv: 4 +0.110 +0.070 +0.035 -0.003 -0.025 +0.003 -0.020 +0.010 +0.027 +0.070
Recv: 5 +0.152 +0.080 +0.035 +0.010 -0.040 -0.012 -0.035 -0.003 +0.015 +0.060
Recv: 6 +0.118 +0.073 +0.032 +0.017 -0.010 +0.035 +0.015 +0.045 +0.080 +0.132
Recv: 7 +0.252 +0.182 +0.127 +0.102 +0.065 +0.080 +0.057 +0.080 +0.090 +0.123
Recv: 8 +0.223 +0.165 +0.118 +0.090 +0.070 +0.100 +0.088 +0.142 +0.162 +0.225
Recv: 9 +0.245 +0.202 +0.155 +0.135 +0.080 +0.130 +0.090 +0.147 +0.182 +0.232
Recv:
Recv: X:319.00 Y:293.00 Z:9.67 E:0.00 Count X:25520 Y:23440 Z:4000
Recv: ok P15 B3