ValueError: problem with broadcast from shape (16,16,21) into (16,16)

[LukasEssig]

When I run the code from the Single Shot Multibox Detector (SSD), I get the following error:

ValueError: could not broadcast input array from shape (16,16,21) into shape (16,16).

To be more precise, it occurs running the following code:

model %>% fit_generator(
train_gen,
steps_per_epoch = steps_per_epoch,
epochs = 5
callbacks = callback_model_checkpoint("weights_withbg.{epoch:02d}-{loss:.2f}.hdf5",
save_weights_only = TRUE)
)

Does anyone have the same problem?

Edit 08.10.2019:
A new release of keras for R came out today, namely keras version 2.2.5.0 for R. I don't get
the error from above anymore. Lucky coincidence. I used keras 2.2.4.1 for R before.