Why does Walklex return spaces before some of the field names, but fieldsummary does not?

[Derson]

Why does Walklex return spaces before some of the field names, but fieldsummary does not? When I see this without field extractions causing spaces in the field names, it usually looks like "special" fields this happens to. But these fields don't seem to exist if I try to search for or using them.

Is this as simple as an output parsing bug from walklex or an indexing bug adding a space? If so, 
1. Should the space be trimmed or the event be removed to get the correct results?
2. Any context on why this is happening with specific fields?

fieldsummary command with no spaces in field names:

index=indexName
| fieldsummary
| stats count by field

Example results from fieldsummary:

field

host

source

sourcetype

timestamp

walklex command with spaces in field names:

| walklex index=indexName type=field
| stats count by field

Example results from walklex:

field

host

timestamp

host

timestamp

[rderson]

Splunk stores everything in lower case, but fields are case sensitive. You'll notice that all the fields returned by Walklex that have a space at the start return with the correct case. Walklex is revealing the hidden backend way that Splunk stores case-sensitive field names.