Mosaic error

Hi,
pelase consider looking into mosaic function. I probably found error. I was trying to implement Albumentations pipeline and all the time got an error .... so I started to debug code and found that mosaic algorithm generate targets with size 0 ... Look here:

I print only targets in call function

class TrainTransform:
    def __init__(self, max_labels=50, flip_prob=0.5, hsv_prob=1.0):
        self.max_labels = max_labels
        self.flip_prob = flip_prob
        self.hsv_prob = hsv_prob

   def __call__(self, image, targets, input_dim):
        print("TRAIN TRANSFORM")  
        print(targets)   # I print only targets

Case #1 - no mosaic - everything works perfectly

TRAIN TRANSFORM
[[647.5 213.75 736.25 282.5 0. ]]
TRAIN TRANSFORM
[[403.75 111.25 445. 146.25 0. ]]
TRAIN TRANSFORM
[[ 87.5 732.5 180. 800. 0. ]]
TRAIN TRANSFORM
[[1358.75 656.25 1417.5 718.75 0. ]]
TRAIN TRANSFORM
[[492.5 213.75 531.25 260. 0. ]
[376.25 336.25 417.5 375. 0. ]]

Case 2 - mosaic prob = 1

[ 924.27274024 960. 1027.35195473 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1440.94550157 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[ 253.86266154 225.81551197 267.52665749 237.32203487 0. ]
[ 171.15952818 146.70816701 202.08330848 169.72121282 0. ]]

[ 0. 724.68044514 0. 762.38348968 0. ]
[ 793.23250337 602.66065369 852.39074366 659.05887883 0. ]
[ 0. 960. 0. 960. 0. ]
[ 0. 960. 0. 960. 0. ]
[1351.49268456 960. 1395.86564479 960. 0. ]
[1306.2176049 960. 1365.95252008 960. 0. ]
[1134.91053628 960. 1176.97962312 960. 0. ]
[ 897.39548351 960. 930.70017725 960. 0. ]
[ 483.42069316 178.34964884 529.4976874 220.8822589 0. ]]

[1600. 0. 1600. 48.58649928 0. ]
[1600. 17.36227029 1600. 76.92993114 0. ]
[1152.51476424 960. 1250.6877682 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1600. 960. 1600. 960. 0. ]
[1253.83566329 840.65383707 1323.14144987 913.80994513 0. ]
[1074.79571461 64.81405945 1142.17634046 141.82048899 0. ]

`self.data_num_workers = 2
self.num_classes = 1

    self.input_size = (960, 1600)
    self.random_size = (10, 25)
    self.test_size = (960, 1600)

    # --------------- transform config ----------------- #
    self.mosaic_prob = 1
    self.mixup_prob = 0.5
    self.hsv_prob = 0
    self.flip_prob = 0.1
    self.degrees = 10.0
    self.translate = 0.1
    self.mosaic_scale = (0.1, 2)
    self.mixup_scale = (0.1, 2)
    self.shear = 2.0
    self.enable_mixup = True
    self.multiscale_range = 5`

Start at TrainTransform.call and trace the mosaic path using the provided configuration, especially mosaic_prob=1, input_size=(960, 1600), and mosaic_scale=(0.1, 2). Reproduce the printed targets and identify why boxes are produced with zero height or width; done means mosaic targets remain valid and the Albumentations pipeline no longer fails.