From your pictures, it looks like you do have crape myrtle bark scale.  Unfortunately, it's becoming common in our area.  A soil drench applied in the spring is the best way to control crape myrtle bark scale.  Insecticidal sprays are best applied in April and May and late summer.

Here is some information on crape myrtle bark scale and how to treat it.

Crapemyrtle Bark Scale | Home & Garden Information Center (clemson.edu)

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