Code suggestion doesn't appear to work consistently

[JRDK92]

Using VS Code 1.97.0, and Python code suggestion doesn't appear to work consistently. Here's what happens when I type .merge(

However, later on, when I do another merge later in the script... it will no longer suggest any insight on code. Why ?

Here's some sample code.

import pandas as pd
import ace_tools as tools

sales_data = pd.DataFrame({
    'customer_id': [1, 2, 1, 3, 2, 4],
    'product_id': [101, 102, 103, 101, 104, 103],
    'quantity': [2, 1, 5, 3, 2, 4],
    'transaction_date': ['2025-01-01', '2025-01-02', '2025-01-03', '2025-01-04', '2025-01-05', '2025-01-06']
})

product_data = pd.DataFrame({
    'product_id': [101, 102, 103, 104],
    'product_name': ['Product A', 'Product B', 'Product C', 'Product D'],
    'price': [20, 35, 15, 25]
})

sales_data = sales_data.merge(product_data, how='left', left_on='product_id', right='id')

When I started typing into sales_data dataframe to do that merge, I got a code completion/suggestion snippet. So it worked here...

output_df = cust_rev.merge(sales_data[['customer_id', 'total_spent']],on='customer_id', how='left').drop_duplicates()

When I got later on in my script to this part above... no suggestion. Had to type the whole thing, had no popup to suggest any python code or help with parameters. What causes this?