Hello im newbie in neural network , i have written a model CNN architecture Resnet50 using google colab after train my model then saving models afterwards load model without restart run time get same result but why when restart runtime google colab and run xtrain,ytest,x_val,y_val then load model again getting different result

here my code from setting parameter

#hyperparameter and callback
batch_size = 128
num_epochs = 120
input_shape = (48, 48, 1)
num_classes = 7

#Compile the model.
from keras.optimizers import Adam, SGD
model = ResNet50(input_shape = (48, 48, 1), classes = 7)
optimizer = SGD(learning_rate=0.0005)
model.compile(optimizer= optimizer, loss='sparse_categorical_crossentropy', metrics=['accuracy'])

model.summary()
history = model.fit(
    data_generator.flow(xtrain, ytrain,),
    steps_per_epoch=len(xtrain) / batch_size,
    epochs=num_epochs, 
    verbose=1,
    validation_data= (x_val,y_val))

import matplotlib.pyplot as plt 
model.save('Fix_Model_resnet50editSGD5st.h5')

#plot graph
accuracy = history.history['accuracy']
val_accuracy = history.history['val_accuracy']
loss = history.history['loss']
val_loss = history.history['val_loss']
num_epochs = range(len(accuracy))
plt.plot(num_epochs, accuracy, 'r', label='Training acc')
plt.plot(num_epochs, val_accuracy, 'b', label='Validation acc')
plt.title('Training and validation accuracy')
plt.ylabel('accuracy')  
plt.xlabel('epoch')
plt.legend()
plt.figure()
plt.plot(num_epochs, loss, 'r', label='Training loss')
plt.plot(num_epochs, val_loss, 'b', label='Validation loss')
plt.title('Training and validation loss')
plt.ylabel('loss')  
plt.xlabel('epoch')
plt.legend()
plt.show()

#load model
from keras.models import load_model
model_load = load_model('Fix_Model_resnet50editSGD5st.h5')

model_load.summary()


testdatamodel = model_load.evaluate(xtest, ytest) 
print("Test Loss " + str(testdatamodel[0]))
print("Test Acc: " + str(testdatamodel[1]))

traindata = model_load.evaluate(xtrain, ytrain) 
print("Test Loss " + str(traindata[0]))
print("Test Acc: " + str(traindata[1]))

valdata = model_load.evaluate(x_val, y_val) 
print("Test Loss " + str(valdata[0]))
print("Test Acc: " + str(valdata[1]))

-after training and saving model then run load model without restart runtime google colab : as you can see the Test get loss: 0.9411 - accuracy: 0.6514

Train get loss: 0.7796 - accuracy: 0.7091

ModelEvaluateTest & Train

just run load model again after restart runtime colab:

Test get loss: 0.7928 - accuracy: 0.6999

Train get loss: 0.8189 - accuracy: 0.6965

after Restart Runtime Evaluate test and train