How to format sequences to store in experience buffer for DRQN?

For DRQN (Deep Recurrent Q Learning) in POMDP it is needed to store entire sequences instead of individual transitions in the replay buffer. For the object agent.ExperienceBuffer, how to construct the data? For example, for Observation element i have tried to have a 1x1 cell with inside the numchannel x sequencelength, and also to have a cell array directly numchannel x sequencelength. the idea was to then sample minibatch of sequences instead of minibatch of transitions.

For any trial I get an error

Error using rl.replay.rlReplayMemory/validateExperience
Observation dimensions must match the dimensions specified in the corresponding specifications.

More specifically, when debugging i see that in the first case (1x1 cell) the code crashes at :

for obsCh = 1:numObsChannels
    if ~all(size(NewObs{obsCh}) == obj.InternalReplayMemory_.ObservationDimension{obsCh})
        error(message('rl:general:errIncorrectObservationDim'));
    end
    

And in the second case at:

    if numObsChannels ~=  numel(NewObs)
        error(message('rl:general:errIncorrectObservationDim'));
    end   

In MATLAB it is possible to have dqn with recurrent layers, so there is certainly a way to store these sequences somehow.

Thank you,

Imola