Mark labels set to "Always Show" on a map do not always show

Issue

When turning on Mark Label > Always Show for a mark on a map view, the label only shows at certain zoom levels

Environment

Tableau Desktop

Resolution

Create a dual axis map where one axis uses a calculation that returns only the label values that should always show. Set that axis to "Allow labels to overlap marks"

The attached example workbook uses the sample data set Superstore to demonstrate the following directions:

Doublie click Lontitude and Longitude fields to create a map
Add City to Labels
Ctrl+drag [Latitude (generated] next to itself on the Rows shelf. This will create another copy of [Latitude (generated)]
Select Analysis > Create Calculated Field
In the Calculated Field dialog box that opens, do the following, and then click OK:
1. Name the calculated field. In this example, the calculated field is named "Always Show Cities"
2. In the formula field, create a calculation similar to the following:
```
IF [City] = "San Francisco" OR [City] = "Seattle" THEN [City] END
```
Click Marks card named Latitude (generated) (2) to open the Marks card
Replace [City] on Label with [Always Show Cities]
Click Label and check Allow labels to overlap other marks
Right-click on the second copy of [Latitude (generated)] on the Rows shelf and click Dual axis