Using several transformer models, when using plot_forecast(time_series=ts_test), an error occurred.[BUG]

[Kevin-shengAAA]

Describe the bug
Using several transformer models, when using plot_forecast(time_series=ts_test), an error occurred.

To Reproduce
RuntimeError: The size of tensor a (2) must match the size of tensor b (142) at non-singleton dimension 1

Expected behavior

Screenshots

Desktop (please complete the following information):

• OS: [e.g. win10]
• Merlion Version: latest

[Kevin-shengAAA]