Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 560/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 391.35
Broken: version: 2.80 (sub 57), branch: master, commit date: 2019-04-14 19:18, hash: rB860a9f979d60
Short description of error
All this for Workbench render engine.
If you decide to render what you see inside viewport, by pressing View>Viewport Render Image. if will have two difference on rendered image.
First: if you've chosen some different mode than solid mesh (Display as wires or bounds) - it will have different result in viewport and at the render. On render it always shows wire+mesh or bound+mesh.
And second one - that "axis grid" on render looks a bit another than at viewport. On render it more fat (less appeal).
Exact steps for others to reproduce the error
You can open file and then press View>ViewportRenderImage
Open default. Choose Render engine: Workbench. Press Z -> solid mode. Go to ViewportShading menu and choose Color: Object mode. Go to Output menu and change render % resolution to 43%
Delete cube and light. Press Num0 [camera view] Put plane and scale it to fill camera shoot. Go to properties>Object>ViewportDisplay and choose another then white color (not white - for better visibility axis grid)
Put Monkey. Go to Properties>Object>ViewportDisplay>DisplayAs and choose at first Wire [and same issue with bounds].
Then press View>Viewport render image/animation. Compare results: what you see in viewport and what you see as viewport-rendered. Done.
You will see that grid lines more thiker and monkey have solid+mesh