Why using imagesc and plotResponse to plot range-doppler map give different magnitude level?

I am using the phased.RangeDopplerResponse and the dechirped signal xr_con to generate the range-doppler response. The code is given below. With the same xr_con here, why the imagesc and plotResponse give different maximum magnitude output?

For imagesc, the maximum magnitude is 46.1634 but the plotResponse gives 56.1634, where there is exactly a 10 dB difference here.

As far as I know, for default of plotResponse, the magnitude is in 'dB' as well.

I checked that, for magnitude, both plots are the same. However, for dB plot, somehow, they are different.

rngdopresp = phased.RangeDopplerResponse('PropagationSpeed',c,...

'DopplerOutput','Speed','OperatingFrequency',fc,'SampleRate',fs,...

'RangeMethod','FFT','SweepSlope',slope,...

'RangeFFTLengthSource','Property','RangeFFTLength',1024,...

'DopplerFFTLengthSource','Property','DopplerFFTLength',256);

% clf;

[resp,rng_grid,dop_grid] = rngdopresp(xr_con);

figure;

imagesc(dop_grid,rng_grid,mag2db(abs(resp)));

xlabel('Speed (m/s)');

ylabel('Range (m)');

title('Range-Doppler Map');

figure;

plotResponse(rngdopresp,xr_con); % Plot range Doppler map

axis([-v_max v_max 0 d_max])

clim1 = caxis;