Hi Steve,
Thank you for contacting Syncfusion support.
We have prepared the sample based on your code snippet. We are not able to reproduce the issue. For your convenience, we have prepared a sample. Please find the below sample link.
In provided code snippet, you have provided width for div.col-md-12 element, this width breaks the behavior of bootstrap grid layout support.
Also please share the detail in which action, you are facing this issue. Whether you are facing the issue in load time or while changing from hidden state to visible state? Also please modify our sample so that, it will be very helpful to check in our end.
Regards,
Saranya D